This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to do pull ups for beginners
Do flexed arm hangs.
To build muscles in your shoulders and arms, start with flexed arm hangs. To do flexed arm hangs, place a box near the pull up bar that puts your chin just over the bar.

Choose from:
[a]. Then put your arm through the box, and allow your thumb and index finger to rest on top of the weight. Carefully transfer the weight to your free arm.
[b]. Place the box to your right side so your feet are flat on the ground. Then lean forward over the bar so your face is towards the bar.
[c]. Release the box and lower your arms down so they are horizontally perpendicular to the bar. Use your non-dominant hand to support your lower back, offering a firm grip.
[d]. Place your hands on the bar with your palms facing you. Lift yourself upward and hold yourself slightly over the bar.
The answer is:
[d].