Given the task definition and input, reply with output. 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".

People run motocross on a bumpy road in the wood. A person climbs a bump with a motorcycle. also people <sep> (A) climb a rough platform high up. (B) stand in a log where a man holds a light throwing it near steep and narrow hill as a guide. (C) rides motorcycles on an unpaved flat surface. (D) riding horses through road.
C