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: SPORTS 
Clue: Football's imaginary plane which neither team may cross until the ball is snapped

SOLUTION: the line of scrimmage

PROBLEM: Category: BARTLETT'S FAMILIAR QUOTATIONS 
Clue: The latest "Bartlett's" lists quotes chronologically; the first quotes come from this country

SOLUTION: egypt

PROBLEM: Category: 30 YEARS AGO: SEPTEMBER 1967 
Clue: Like a rock this dependency voted to remain solidly under British control

SOLUTION:
gibraltar