Please choose the correct ending to complete the given sentence: Finance and Business: [header] How to sit up straight at a computer [title] Face forward. [step] Keep your torso and neck in line. Ensure your back is adequately supported, with a slight curvature in your lower back.

Ending1: Follow this curve with your elbows and knees toward your feet. Do not lean forward to center your weight on this curve. Ending2: Stretch that side out a bit more, making sure to keep your back straight. [substeps] For better posture you can lay down on top of a desk. Ending3: Keep your head level and your eyes looking ahead of you. Do not tilt your head to one side or the other. Ending4: ( grab even if you start to feel hurt/sensation like your back might rip. ) [title] Keeping your spine straight with your lower back slightly arched.

Answer format: ending1/ending2/ending3/ending4