Answer the following 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 Central Powers , consisting of Germany, , the Ottoman Empire and Bulgaria  hence also known as the Quadruple Alliance  was one of the two main factions during World War I (191418). It faced and was defeated by the Allied Powers that had formed around the Triple Entente, after which it was dissolved.  - Air Vice Marshal Sir Charles Alexander Holcombe Longcroft KCB , CMG , DSO , AFC ( 13 May 1883 -- 20 February 1958 ) was a pilot and squadron commander in the Royal Flying Corps who went on to become a senior commander in the Royal Air Force .  - 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 Royal Flying Corps (RFC) was the air arm of the British Army before and during the First World War, until it merged with the Royal Naval Air Service on 1 April 1918 to form the Royal Air Force. During the early part of the war, the RFC supported the British Army by artillery co-operation and photographic reconnaissance. This work gradually led RFC pilots into aerial battles with German pilots and later in the war included the strafing of enemy infantry and emplacements, the bombing of German military airfields and later the strategic bombing of German industrial and transportation facilities.    What object entity has the relation of 'conflict' with the subject 'charles longcroft'?   Choices: - battle of britain  - the blitz  - world war  - world war i
Answer:
world war i