Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to build a ninja warrior course [title] Find a good spot to build your course. [step] Pick the spot where you want to build your course before you draw up your plans, since you might have to account for narrow spaces, low-hanging tree branches, or other environmental factors. [substeps] Pick a spot that's free of dangerous obstructions like protruding tree roots or sharp rocks.

Ending1: The best place to build is a big, open backyard where you'll have plenty of room to run, jump, and swing. Take measurements of the space where you want to build so you can plan the exact dimensions of your course. Ending2: Ensure that the spot is level, and always keep the area away from rain. Don't water the area afterward because this could cause splashing and other bad outcomes. Ending3: You can build your course here, or in some alternative way make the space more secluded. [title] Find the area you want to build your course. Ending4: There's no reason to draw up your plans in a dense forest because many ninja practice in bushes, making it harder for people to sneak up on the camp. [title] Decide what to do with your materials.

Answer format: ending1/ending2/ending3/ending4