Please choose the correct ending to complete the given sentence: Cars & Other Vehicles: [header] How to do an in flight fitness workout [title] Sit in your seat with your feet flat, hip-width apart and directly underneath your knees. [step] Lift your heels up so that only the balls of your feet are on the floor. Hold this position for five seconds and then lower your heels.

Ending1: Don't even touch your toes with your heels on the floor. [title] Stretch your arms out in front of you. Ending2: Repeat this movement 10 times, making sure that your breathing is natural and at a regular pace. [title] Lift the balls of your feet so that only your heels are on the floor. Ending3: There is no need to touch any one of your feet. Do not try to touch many other areas. Ending4: [substeps] Try not to take all of the weight off your feet, but keep your knees on the floor. Focus your attention on your center of balance while you sit.

Answer format: ending1/ending2/ending3/ending4