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.

Category: SKIP TO MY "LU" 
Clue: It's the capital city of Zambia
lusaka

Category: BODY LANGUAGE 
Clue: When vou're idle or just plain bored, you do this with your pollex digits, literally or figuratively
twiddle your thumbs

Category: EMPIRES 
Clue: Alpaca wool was a major commodity in this empire that peaked in the 1400s

the inca empire