Please choose the correct ending to complete the given sentence: Pets and Animals: [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.

Ending1: [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. Ending2: 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. Ending3: [substeps] Choose a fence material that meets your budget. Wood, steel, chain-link, and plastic all make good fencing materials. Ending4: [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.

Answer format: ending1/ending2/ending3/ending4