instruction:
You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For consistency, answers should be in all lower cased letters.
question:
Category: THE RUSSIANS ARE COMING 
Clue: On April 14, 1961 this cosmonaut was awarded the honor "Hero of the Soviet Union"
answer:
gagarin


question:
Category: 12-LETTER WORDS 
Clue: Meaning a beginning, it's also a school graduation ceremony
answer:
commencement


question:
Category: KINGS & THEIR CASTLES 
Clue: William the Conqueror chose the site of this huge castle, one day's march from the Tower of London
answer:

windsor castle