A. wrap the bandage in a circle.
B, firstly fix it in a ring for several times, and then wind it downwards, with each circle covering 1/3 ~ 2/3 of the previous circle.
C, first fix it into a ring by winding several times, and then wind it up. Fold the bandage back once a week at the gradually thickened place, cover it with 1/3 ~ 2/3 of the previous circle, and wrap it from bottom to top.
D from bottom to top, then wrap the bandage from top to bottom at the top and bottom of the joint bend (correct answer).