(a) would be my choice. Here's an example dialogue:
Max: Let's go see a movie. There are three new flicks playing at the Grand Cinema.
Pat: OK, but I have to work late, so let's go to the late one.
Max: One starts at 8:00, another at 8:15, and the other one starts at 8:30.
Pat: Whichever one starts the lateness is fine with me.
Max: That's the 8:30 movie.
Pat: Sounds good. I'll meet you at the Grand.