Detailed 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".
Q: He is putting training wheels on the back wheel of the bike. He puts the front tire on the bike. He puts the handlebars on the bike. he <sep> (A) puts the pedals onto the bike. (B) puts the spare tire on the bike. (C) puts on either helmet. (D) puts the jack on the bike, he puts go of the tire on the handlebars.
A:
A