Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to build a concrete pool [title] Mark out and excavate the area of the yard to install the concrete pool. [step] The hole should be dug approximately 9 to 12 inches (23 to 31 cm) deeper than you want the depth of your pool, to allow room for surfacing the bottom of the basin. A lip is also left around the perimeter of the hole to accommodate sufficient working room for placing forms.

Ending1: [title] Install plumbing, using pvc pipe and strong bonding material. [step] Your plumbing should include a drain at the bottom of the pool as well as the necessary structure to ensure safe water flow throughout the pool. Ending2: Post posts, sliding rails, and poles work well to secure the wooden frames. [substeps] Plaster mesh works well to supplement the space needed. Ending3: [title] Run your hands over the edge of the foundation to ensure that it is level and level. [step] Post and brace edging is the intended purpose of the gravel tub. Ending4: A reasonable amount of cement will be made of concrete that is water-based. [substeps] Collect the concrete according to its package, refilling occasionally to maintain drainage and cracks during the digging process.

Answer format: ending1/ending2/ending3/ending4