This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Which of the following represents site of reversal of polarity of myosin molecules in thick muscle filaments? 
Select and explain. 
A. M line, B. Z line, C. I line, D. H line
A: M line
Answer: A: M line 
Explanation: The M line is the site of the reversal of polarity of the myosin molecules in each of the thick filaments. At these points, there are slender cross-connections that hold the thick filaments in proper array.