Given the task definition and input, reply with output. In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").

if you see little wet spots on your windshield, what might have happened? (A) the sun is setting (B) vapor transformed into droplets (C) the moon is rising (D) the windshield is dissolving
B