Q: 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".
The video begins with the annual bmx biking event where several participants are gathered to begin their competitive event. Several bikers begin biking on their bikes on curved slopes in the open air arena. the bikers <sep> (A) line up to begin their routine and they do some tricks as a race begins. (B) go over bumpy and hilly slopes in their gears and helmets. (C) compete, much to the public's disappointment. (D) all begin to u-turn as they are being pushed forward.
A:
B