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.

[EX Q]: Context : Trace of Stones (German: Spur der Steine) is a 1966 East German film by Frank Beyer. 
Answer : Spur der Steine
[EX A]: The Trace of Stones is based upon what?

[EX Q]: Context : The 1982 El Salvador earthquake occurred on 19 June 1982 at 00:21 local time (06:21 UTC). 
Answer : 19 June 1982
[EX A]: When did 1982 El Salvador earthquake occurr?

[EX Q]: Context : Lina Prokofiev (born Carolina Codina, 21 October 1897 -- 3 January 1989) was a Spanish singer and the wife of Russian composer Sergei Prokofiev. 
Answer : Sergei Prokofiev
[EX A]:
What is Lina Prokofiev's spouse's name?