The right option is; d. a hyperextended knee
The standing toe touch is a form of exercise that is performed to stretch the body. During this exercise, an individual bends over from the hips and waist in an attempt to touch the toes. If the standing toe touch exercise is not done properly, it is most likely to result in a hyperextended knee; a condition that occurs when the knee is bent backward. Certain structures in the knee such as cartilage, and ligaments can be damaged by a hyperextended knee.