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".
Input: [header] How to teach your dog to heel [title] Find a quiet place to train your dog. [step] You want to eliminate distractions, so that your dog can concentrate on you easily. If you have a backyard, that is the perfect place to train your dog. <sep> (A) Otherwise, find a quiet corner of a park with few other people or pets. If outdoors is too distracting, start inside. (B) However, if you have a big backyard, that may not be a good idea. You want to build up flexibility, so make sure your fenced in area or your backyard is not far from your dog's park or home. (C) However, you should never put your dog in a fenced-in yard. Additionally, you cannot put your dog in a shelter for two reasons. (D) Choose a place where your dog can stand and extend the leash lightly, pulling it close to your side of the yard. Now it is time to get this training started.
Output:
A