Instructions: 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". 
Input: A man is kneeling down on an orange mat. he <sep> (A) is using a blue pump to pump blood into his feet. (B) pulls a rope on an exercise machine. (C) lifts his face up to the camera and holds up a black mat. (D) uses a metal brush to wipe green off of the mat.
Output:
B