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: I NEED "HOPE" 
Clue: It weighs 45.52 carats
the hope diamond

Category: PRESIDENTIAL FIRSTS 
Clue: 1st president to refuse a 3rd term
george washington

Category: FRATERNITIES & SORORITIES 
Clue: In 1902 Pi Beta Phi was a founding member of the NPC, this "National Conference" of Greek-letter societies

national panhellenic conference