Please choose the correct ending to complete the given sentence: Tumbling: A gymnast runs, then flips several times down an indoor track. other girls

Ending1: in different costumes watch him run. Ending2: do flips in elliptical environments for both for exercise and dancing. Ending3: is in the background watching him. Ending4: follow suit, flipping quickly as they go.

Answer format: ending1/ending2/ending3/ending4