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]: Actor who plays john bates in downton abbey?
[A]: Brendan Coyle


[Q]: Who is the nobel peace prize named for?
[A]: Alfred Bernhard Nobel


[Q]: When did trick or treating begin in america?
[A]:
1920s