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: 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
conundrum

Category: THE FEMALE EQUIVALENT 
Clue: The Northland College LumberJacks
the lumberjills

Category: QUOTATIONS 
Clue: Karl Marx: this "is the opium of the people"

religion