Teacher: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". 
Teacher: Now, understand the problem? Solve this instance: A man is standing inside a workshop. he <sep> (A) is using a bicycle a is laying on the ground. (B) is welding something on the ground in front of him. (C) leans over, welding a piece of metal. (D) is rubbing the ice off of a car with a brush.
Student:
C