Correct Answer: Lactic Acid

Solution : The correct option is Lactic Acid.

Numerous reasons, such as the build-up of metabolic wastes like lactic acid, the exhaustion of energy stores (like ATP), faulty neurotransmitter communication, reduced oxygen delivery, and waste product accumulation, can cause muscle weariness. Inadequate rest, excessive muscle use, and insufficient recovery time in between activities might all be contributing factors.