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 simplicity, answers should be in all lower cased letters.

[Q]: Category: LANDMARKS 
Clue: Some of its pieces, which weighed up to 50 tons, were quarried at Marlborough Downs, about 20 miles away
[A]: stonehenge


[Q]: Category: ASIAN HISTORY 
Clue: This peninsula of 85,000 square miles was ruled by a single dynasty from 1392 to 1910
[A]: korea


[Q]: Category: 1950s ACHIEVEMENTS 
Clue: On Nov. 20, 1953, in a Douglas D-558-2, Scott Crossfield reached this benchmark
[A]:
traveling twice the speed of sound