Given the task definition and input, reply with output. Generate a question which can yield the answer mentioned in the input. Generated question must be answered by the answer provided in input, without using any extra knowledge.

Context : Waldemar Mehl (7 September 1914 in Gravenwiesbach, Hesse--29 March 1996 in Wiesbaden) was a German U-boat commander during World War II, and recipient of the (German: Ritterkreuz des Eisernen Kreuzes).
Answer : World War II
What war was Waldemar Mehl in?