Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to train a bully breed dog [title] Get the right collar and leash. [step] The collar and leash you choose for your dog is often a matter of aesthetics, but with bully breeds you'll need to keep practical considerations in mind. Remember that because bully breed dogs tend to be stout and muscular, collars and leashes made of strong, unbreakable materials are the best way to control your pet.

Ending1: [substeps] Aggressive dogs tend to require a thick collar and a leash. If your dog is unusually stiff or aggressive, collar and leash work well. Ending2: Therefore, you may want to get a collar with chain links instead if you want to keep these dogs and their companions safe while you train them. [title] Do not allow the dog to be distracted. Ending3: [substeps] Stand outside the dog's home and do not ever touch your pet without a collar or leash. Do not lead the dog on walkways or out while it is browsing another dog's property. Ending4: [substeps] Try a head collar like those made by gentle leader. These redistribute pressure so that your dog is not injured by pulling on the leash.

Answer format: ending1/ending2/ending3/ending4