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: 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: INSURANCE 
Clue: It's a payment on an insurance policy or a ranking, especially for a brand of saltine
premium

Category: SUBMARINES 
Clue: Air trapped in these tanks makes a sub float

ballast tanks