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: BROADWAY MUSICALS 
Clue: 1960 musical that contains the line: "Your table is cracking...can you hear the timbers split?"

SOLUTION: \"camelot\"

PROBLEM: Category: SPORTS BOOKS 
Clue: In 1998 the author of this controversial 1970 book was finally invited to play in a Yankees old-timers' game

SOLUTION: \"ball four\"

PROBLEM: Category: BUSINESS & INDUSTRY 
Clue: It's the biggest single customer of the domestic airline industry, using about 15,000 flights a day

SOLUTION:
the us postal service