Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to trailer a horse [title] Park the trailer. [step] It should be in a level area with good footing for the horse, and with enough space for you to easily access all the doors. [title] Perform a safety check.

Ending1: [step] Before entering the area, check that the front door and the trailer lid are solid. If there is an issue with solid doors, replace the door and lock it behind the rider. Ending2: [step] Walk around the trailer and check to see if the wheels are flat. If the wheels are flat, then you are good to go. Ending3: [step] In a trailer, the only way to tell if the horse is in distress or not is to check its feet for signs of damage. If you see any shattered toes, it means a horse is in distress. Ending4: [step] Before loading the horse, be sure the trailer and tow vehicle are in perfect order. [substeps] Check for broken rivets or screws or any other sharp metal edges.

Answer format: ending1/ending2/ending3/ending4