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: PHONING IT IN 
Clue: Reflecting the company's activities at its founding in 1885, it was the second "T" in AT&T

SOLUTION: telegraph

PROBLEM: Category: THE 19th CENTURY 
Clue: 1853 purchase that brought the contiguous U.S. about up to its present area

SOLUTION: the gadsden purchase

PROBLEM: Category: GREEK MYTHOLOGY 
Clue: This most powerful Greek god was also the god of justice & the god of oaths & hospitality

SOLUTION:
zeus