The correct option is A Carbohydrates
Carbohydrate is essential as the most immediate and efficient fuel to the muscles. In its circulating form in the blood, carbohydrate is called as glucose, and its storage form in muscles and in the liver is called as glycogen. When the athlete first begins to exercise, body draws on the circulating glucose as its first source of energy. Glycogen, as the storage carbohydrate, comes in when circulating glucose drops to a lower level. Without enough carbohydrates, performance as an athlete will be seriously impacted.