Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).  

Assertion (A): The reaction time of the fibres can vary in different muscles.  

Reason (R): Red muscle fibres that rely mainly on anaerobic respiration contract faster while white muscle fibres that rely primarily on aerobic respiration contract slower. 

In the light of the above statements, choose the most appropriate answer from the option given below.  

Assertion (A) is true. The reaction time, or the time it takes for muscle fibers to respond to a stimulus, can vary among different muscles. Factors such as the type of muscle fibre (fast-twitch vs. slow-twitch), the type of movement required, and the specific neuromuscular control can influence the response time.

Reason (R) is false. The reason is not true. Red muscle fibers, also known as slow-twitch fibers, rely primarily on aerobic (oxidative) respiration and are adapted for endurance and sustained, low-intensity contractions. White muscle fibers, or fast-twitch fibers, are adapted for rapid, high-intensity contractions and tend to rely more on anaerobic (glycolytic) respiration.