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.

[Q]: Category: THE HISTORY OF APRIL 9th
Clue: 1959: NASA publicly introduces Messrs. Glenn, Shepard & the rest of this program's 7 astronauts
[A]: mercury

[Q]: Category: ABBR.
Clue: Computer users should know that BBS stands for this
[A]: bulletin board system

[Q]: Category: WE THE "PEOPLE"
Clue: This phrase for the Jews refers to Exodus 19:6, "Ye shall be unto me... a holy nation"
[A]:
the chosen people