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 consistency, answers should be in all lower cased letters.
PROBLEM: Category: HOMOPHONES 
Clue: A plant of the parsley family, or a unit to measure the fineness of gold

SOLUTION: carrot/karat

PROBLEM: Category: TIME FOR A "CON"TEST 
Clue: Though it possibly dates from the 16th century, the origin of this word for a punny riddle is a mystery in itself

SOLUTION: conundrum

PROBLEM: Category: CANADIAN SONGBIRDS 
Clue: In December 2007 this chanteuse gave her last performance of the Vegas spectacular "A New Day"

SOLUTION:
celine dion