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: HOLIDAYS AND OBSERVANCES 
Clue: The name of this Jewish holy day means "beginning of the year"
rosh hashanah

Category: STATS FREAK 
Clue: Wilt Chamberlain & this '60s Celtic are the only NBAers to average more than 20 rebounds per game
bill russell

Category: ON THE RADIO 
Clue: In 1984 L.A.'s KDAY became the USA's first station devoted to this genre of music

rap