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".

[header] How to dog proof a yard [title] Install a fence. [step] A sturdy fence is the first step to keeping your dog safe in your backyard. With a good fence, your dog cannot escape the yard and other dogs or animals cannot get into the yard, where they could harm your dog. <sep> (A) [substeps] However, fences can keep your dog protected from aggressive dogs and be a safe choice when it is getting out of the yard. The least recommended thing you can do is have a fence between your yard and any other structures and backyard. (B) A good fence will deter any humans from entering the yard. The fence should then also prevent any open water from entering the yard from the animals. (C) [substeps] Choose a fence material that meets your budget. Wood, steel, chain-link, and plastic all make good fencing materials. (D) [substeps] Consider using rails and tire holes on the back of the fence. Dogs can also chew on rails if they enjoy the feeling of having their paws on something.
C