You will be given a definition of a task first, then some input of the task.
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".

[header] How to enhance your dog's recall [title] Choose a friendly environment for training. [step] Your dog will learn best in an environment where it feels comfortable and stress free. If you try to train your dog's recall in an unfamiliar or stressful environment, your dog will have a hard time paying attention to your commands. <sep> (A) [substeps] Parks and outdoor spaces should be recommended. Consider choosing a park or outdoor area just for the dog's recall. (B) Take several things into consideration in regards to your dog's recall. [substeps] Your dog will learn better by focusing your attention on how it learns your commands. (C) [substeps] The best place to train your dog is in your own yard, since your dog is very familiar with this area and won't feel stressed out. If you don't have a yard, you can take your dog to a familiar park. (D) [substeps] For instance, if your dog is about to go to the bathroom, place your dog on the floor in front of you. Say " toilet " and use one hand to lift up dog's bottom thigh.
Output:
C