Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to teach a bulldog to skateboard [title] Find the right skateboard. [step] The board should be at least an inch wider than your dogs normal stance. Use one with older ball bearings-you want your board to travel about a meter with each push.

Ending1: [title] Introduce your dog to the skateboard. [step] Begin with putting your dog in a carpeted room with the skateboard. Ending2: Above all, have the board's axis facing away from the dog. [title] With the board about an inch from the dog's feet, start spinning it. Ending3: The extra height will influence your point of view. 10 or 20 meters is a perfect size for both you and your dog. Ending4: Much less width can cause injury to your pup. Do not let your elbow get too close to the brake pedal.

Answer format: ending1/ending2/ending3/ending4