The answer is B. Spine stretch
Spine stretch is an exercise to stretch your back bone, which mean your upper body, not the lower one.
NB :
Hip Flexor : To stretch your thigh
Calf stretch & Harmstring stretch : To stretch your lower legs
Ruunig and it is this becasue it makes your muscles retrct over and over agin
The answer would be D because the proportion is 6:9, which could be simplified to 2:3
