Answer:
Option A, Carbohydrates
Step-by-step explanation:
Carbohydrates can be easily and quickly broken down into simple sugar such as glucose, fructose, and galactose which are used as a source of energy.
The unused carbohydrates are stored in the form of glycogen with in the muscle and liver and can be used in future based on requirement. Usually, energy from glycogen is used during intense exercises and workouts.
Hence, option A is correct