Answer:
The correct answer is option C.
Step-by-step explanation:
The correct way to lift a heavy item without hurting your back is to use your leg muscles to provide most of the force needed. Emile could have correctly lifted the box by bending his knees and keeping his back straight. This way he would not have put excess stress on his back, instead he would be using his leg muscles. The correct answer is option C.
I hope this answer helps.