Given a question and its paraphrases, answer the question. The answer should exactly answer all the questions given without any ambiguity. Don't give partial answers.

[Q]: Questions: ['on what date did the mexican revolution end?']
[A]: 1920


[Q]: Questions: ['zip code for big ben london england?']
[A]: sw1a 0aa


[Q]: Questions: ['when did barack obama graduated from harvard?', 'what year did barack obama graduate from harvard law?', 'in which year did barack obama graduate from harvard law school?']
[A]:
1991