In this task, you're given an open-domain question. Your task is to provide an answer to the given question. There is only one unique answer for each question. Your answer should be short, and refer to an entity, date, number, etc. Do not put your answer in the context of a sentence.

[Q]: Where does the earth's magnetic field originate?
[A]: Earth's core


[Q]: Who wrote the book journey to the center of the earth?
[A]: Jules Verne


[Q]: When did williamsburg become the capital of virginia?
[A]:
1699