Task: Text Completion
Input (English): [header] How to stop a skateboard [title] Tail scrape only when going slowly. [step] Tail scraping is a very basic stopping method. When performing it, you can easily lose control of the board without meaning to. <sep> (A) If you have never skied before, there is little you can do to stop it. You will just fall off the skateboard and die. (B) Simply stop the skateboard in a right or left lane of traffic. You will need the tail scrape to slow down dramatically. (C) Try tail scraping when skateboarding casually on a sidewalk or even ground. Use a more restrained method (like controlled slide stopping) in dangerous situations. (D) However, you should take the instant warning to heart. Beware: if you continue to lose control of the board without stopping, the board may break over time.
Output (English): C