Given the task definition and input, reply with output. In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".

People are standing in a swimming pool. they <sep> (A) are playing a game of water polo. (B) put on protective caps to ward off the cold. (C) dip a sponge into the water. (D) push themselves through a hole in the water.
A