Find values A, B and C and multiply them

A married couple is sleeping when the phone rings at 3 a.m. The wife picks up the phone and, after a few seconds, replies, "How am I supposed to know? We're 200 miles inland!" and hangs up.
Her husband rolls over and asks, "Sweetheart, who was that?"
"I don't know, some dumb bitch asking if the coast is clear."