Answer: (c) It decreases the use of both free fatty acids and muscle glycogen.
Explanation:
A hypothesis is a statement which includes a presumed explanation for a phenomena. It includes limited evidences. The statement is required to be tested by the experimental procedures.
C is the correct option as caffeine is a stimulant drug which increases muscular activity and improves the performance. The fatty acids and muscle glycogen both are used during the performance the caffeine has no influence over them.