This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Muscle, Subject name: Physiology
Resting muscle length means? 
Select and explain. 
A. Length of actin and myosin before contraction, B. The length of the muscle fiber at the onset of contraction which is required to attain maximum active tension, C. It is about 4 micrometers, D. Length at which muscle has minimal tension
B: The length of the muscle fiber at the onset of contraction which is required to attain maximum active tension
Answer: B: The length of the muscle fiber at the onset of contraction which is required to attain maximum active tension 
Explanation: Resting length: The length of the muscle fiber at the onset of contraction which is required to attain maximum active tension It is about 2 micrometers. Also known as optimum length. At this state, the ends of actin filaments extending from 2 successive Z disks barely overlap one another.