Information:  - The Kriegsmarine ("War Navy") was the navy of Nazi Germany from 1935 to 1945. It superseded the "Kaiserliche Marine" (German Imperial Navy) of World War I and the inter-war "Reichsmarine". The "Kriegsmarine" was one of three official branchesalong with the "Heer (Army)" and the "Luftwaffe (Air Force)"of the Wehrmacht, the armed forces of Nazi Germany.  - World War II (often abbreviated to WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved the vast majority of the world's nationsincluding all of the great powerseventually forming two opposing military alliances: the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. In a state of "total war", the major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, erasing the distinction between civilian and military resources. Marked by mass deaths of civilians, including the Holocaust (in which approximately 11 million people were killed) and the strategic bombing of industrial and population centres (in which approximately one million were killed, and which included the atomic bombings of Hiroshima and Nagasaki), it resulted in an estimated 50 million to 85 million fatalities. These made World War II the deadliest conflict in human history.  - Trench warfare is a type of land warfare using occupied fighting lines consisting largely of trenches, in which troops are significantly protected from the enemy's small arms fire and are substantially sheltered from artillery. The most famous use of trench warfare is the Western Front in World War I. It has become a byword for stalemate, attrition, sieges and futility in conflict.  - Friedrich Christiansen ( 12 December 1879 -- 3 December 1972 ) was a World War I German seaplane ace who claimed shooting down twenty planes and an airship ; thirteen of those victories were confirmed . During World War II , he was the commander of the German Wehrmacht in the Netherlands ; he was convicted for war crimes after the war .  - Nazi Germany is the common English name for the period in German history from 1933 to 1945, when Germany was governed by a dictatorship under the control of Adolf Hitler and the Nazi Party (NSDAP). Under Hitler's rule, Germany was transformed into a fascist state in which the Nazi Party took totalitarian control over nearly all aspects of life. The official name of the state was "Deutsches Reich" from 1933 to 1943 and "Großdeutsches Reich" ("Greater German Reich") from 1943 to 1945. The period is also known under the names the Third Reich and the National Socialist Period (abbreviated as "NS-Zeit"). The Nazi regime came to an end after the Allied Powers defeated Germany in May 1945, ending World War II in Europe.  - The Wehrmacht (lit. "defence force") was the unified armed forces of Nazi Germany from 1935 to 1946. It consisted of the "Heer" (army), the "Kriegsmarine" (navy) and the "Luftwaffe" (air force). The designation "Wehrmacht" for Nazi Germany's military replaced the previously used term, "Reichswehr" (191935), and was the manifestation of Nazi Germany's efforts to rearm the nation to a greater extent than the Treaty of Versailles permitted.  - An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.  - In general, a civilian is "a person who is not a member of the military or of a police or firefighting force", as defined by Merriam Webster's Dictionary. From the perspective of the U.S. Department of Defense, Chapter 18 of Title 10 United States Code refers to non-military law enforcement officers as civilians since they are employees rather than enlisted personnel, and also in order to distinguish itself from military police. In military and law enforcement slang, the term "Civies" or "Civvies" are often used to refer civilian population or civilian clothing.  - Strategic bombing is a military strategy used in a total war with the goal of defeating the enemy by destroying its morale or its economic ability to produce and transport materiel to the theatres of military operations, or both. It is a systematically organized and executed attack from the air which can utilize strategic bombers, long- or medium-range missiles, or nuclear-armed fighter-bomber aircraft to attack targets deemed vital to the enemy's war-making capability.  - The Reichswehr (English: Imperial Defence) formed the military organisation of Germany from 1919 until 1935, when it was united with the new "Wehrmacht" (Defence Force).  - Hiroshima is perhaps best known as the first city in history to be targeted by a nuclear weapon when the United States Army Air Forces (USAAF) dropped an atomic bomb on the city (and later on Nagasaki) at 8:15 a.m. on August 6, 1945, near the end of World War II.  - Military personnel are members of the armed forces. Usually, personnel are divided into military branches roughly defined by certain circumstances of their deployment. Those who serve in a typical large land force are soldiers, making up an army. Those who serve in seagoing forces are seamen or sailors, and their branch is a navy or coast guard . Marines serve in a marine corps. In the 20th century, the development of powered flight aircraft prompted the development of air forces, serviced by airmen. Designated leaders of military personnel are officers. These include commissioned officers, warrant officers and non-commissioned officers (NCOs). For naval forces, non-commissioned officers are referred to as petty officers (POs). military personnel are instructed to wear dog tags  - The Luftwaffe was the aerial warfare branch of the combined German Wehrmacht military forces during World War II. Germany's military air arms during the First World War, the "Luftstreitkräfte" of the Army and the "Marine-Fliegerabteilung" of the Navy, had been disbanded in May 1920 as a result of the terms of the Treaty of Versailles which stated that Germany was forbidden to have any air force.  - World War I (WWI or WW1), also known as the First World War, or the Great War, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history. Over nine million combatants and seven million civilians died as a result of the war (including the victims of a number of genocides), a casualty rate exacerbated by the belligerents' technological and industrial sophistication, and the tactical stalemate caused by gruelling trench warfare. It was one of the deadliest conflicts in history, and paved the way for major political changes, including revolutions in many of the nations involved.  - An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from large gas bags filled with a lifting gas that is less dense than the surrounding air. In early dirigibles, the lifting gas used was hydrogen, due to its high lifting capacity and ready availability. Helium gas has almost the same lifting capacity and is not flammable, unlike hydrogen, but is rare and relatively expensive. Significant amounts were first discovered in the United States and for a while helium was only used for airships by the United States. Most airships built since the 1960s have used helium, though some have used hot air.    After reading the paragraphs above, we are interested in knowing the entity with which 'friedrich christiansen' exhibits the relationship of 'military branch'. Find the answer from the choices below.  Choices: - aircraft  - army  - artillery  - kriegsmarine  - luftwaffe  - military police  - navy  - nazi party  - reichswehr  - united states army  - wehrmacht
A:
luftwaffe