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.

Category: MARK ANTONYMS 
Clue: The traditional mark of someone who can't sign his name has this opposite in tic-tac-toe
o

Category: THE NEW YORK TIMES SCIENCE TIMES 
Clue: Scholars can't read a 10-word column found in Guatemala but know it means these people had writing in 2300 B.C.
the mayans

Category: AMERICAN HISTORY 
Clue: Contrary to myth, Washington didn't throw one of these across the Potomac; there weren't any when he was young

silver dollar