Given the question: Information:  - The Battle of Britain (German: "die Luftschlacht um England", literally "Air battle for England") was a combat of the Second World War, when the Royal Air Force (RAF) defended the United Kingdom (UK) against the German Air Force (Luftwaffe) attacks from the end of June 1940. It is described as the first major campaign fought entirely by air forces. The British officially recognise its duration as from 10 July until 31 October 1940 that overlaps with the period of large-scale night attacks known as the Blitz, while German historians do not accept this subdivision and regard it as a campaign lasting from July 1940 to June 1941.  - The Royal Air Force (RAF) is the United Kingdom's aerial warfare force. Formed towards the end of the First World War on 1 April 1918, it is the oldest independent air force in the world. Following victory over the Central Powers in 1918 the RAF emerged as, at the time, the largest air force in the world. Since its formation, the RAF has taken a significant role in British military history, in particular, playing a large part in the Second World War where it fought its most famous campaign, the Battle of Britain.  - 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.  - Raymond Towers `` Ray '' Holmes ( 20 August 1914 -- 27 June 2005 ) was a British fighter pilot who was feted by the press as a war hero who saved Buckingham Palace from being severely damaged by German bombing during the Battle of Britain . Born in Liverpool , Holmes worked inially as a journalist before joining the RAFVR in 1937 . In June 1940 he joined No. 504 Squadron . On 15 September 1940 , Sergeant Holmes was flying a Hawker Hurricane fighter when he spotted a damaged Dornier Do17 bomber of KG 76 apparently making a bombing attempt on central London . Avoiding the bomber 's return fire , Holmes made a head - on attack on the Dornier , however upon firing discovered his machine guns failed . Holmes decided to ram the bomber hoping his plane could withstand the impact and cut through it . He cut the tail off the bomber with his wing , causing the bomber to crash near Victoria tube station . His Hurricane was badly damaged , crashing near the grounds of Buckingham Palace . Holmes bailed out injured . When recovered , he became part of No 81 Squadron , and was sent to the Northern Front near Murmansk in Soviet Russia to help train the Russian air force in flying the Hawker Hurricane . Here he claimed a further kill ; a Bf 109 F. He was commissioned as a Pilot Officer on 10 June 1941 , promoted to Flying Officer on 10 June 1942 , and Flight Lieutenant on 10 June 1943 . Returning from Russia , Holmes served as an instructor with 2 FIS , Montrose , from 1942 until 1944 . He then flew PR Spitfires with 541 Squadron from February 1945 . After the war , he was a King 's Messenger , personally delivering mail to Winston Churchill , and later a journalist . 65 years later , the wreckage of Holmes ' Hurricane was discovered and successfully excavated from the streets of London . The discovery was featured on the National Geographic Channel documentary , `` The Search for the Lost Fighter Plane '' . Ray Holmes died on 27 June 2005 , aged 90 , following a two - year battle with cancer .    What object entity has the relation of 'military branch' with the subject 'ray holmes'?   Choices: - air force  - luftstreitkräfte  - luftwaffe  - navy  - royal air force  - wehrmacht
The answer is:
royal air force