The Riot at the Stonewall Inn That Began the Modern

The riot at the Stonewall Inn that began the modern movement for equality for gay males and lesbians was sparked by what?

A) A raid by police on a bar popular with gay men and lesbians
B) Refusal of the bar to serve gay and lesbian patrons
C) Anti-gay protestors who showed up at the bar
D) An attempt by a gay couple to hold a marriage ceremony at the bar
E) Refusal of the bar to hire openly gay workers