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 riding spin bikes in a gym. two women <sep> (A) on bikes are lined up on a wooden barrelled court. (B) in overalls are in the gym. (C) wagon in a back wheel. (D) are working out on exercise bikes.
D