Heavier weights and increase repetitions.
Answer:
i mean im 17 but i know about this stuff... ive read up on it
Explanation:
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