TASK DEFINITION: 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.
PROBLEM: Category: FICTIONAL BATTLES & WARS 
Clue: Juan Rico joins the mobile infantry to fight in the war against the invading alien "bugs" in this Heinlein novel

SOLUTION: starship troopers

PROBLEM: Category: WHICH U.S. CABINET DEPARTMENT? 
Clue: The U.S. Geological Survey

SOLUTION: department of the interior

PROBLEM: Category: "A" PLUS 
Clue: A small sum of money given regularly by a parent to a child

SOLUTION:
allowance