Carbohydrates are in place of simple sugars and complex carbs which either are quick energy or stored energy for performance. Without carbs, the body will shut down because you need sufficient energy to keep going. Carbs are what keeps you moving and functioning.
The answer for the picture put up is D, not C.
D is the correct answer.
The ansewer is d. I don't really wanna explain it but I need more letters to post answer :)