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".
Q: He hooks the air pump up to the tire. Tools are sitting on a brick wall. He turns the bike upside down to look at the tire. he <sep> (A) fixes the bricked supports in the tire. (B) puts the tire on the bike. (C) takes a nut off of the wheel to get the tire off. (D) removes a roller and tightens the flat and sets it back on the tire.
A:
C