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
The skeletal muscle action potential: 
Select and explain. 
A. Is not essential for contraction to occur, B. Has a prolonged plateau phase, C. Spreads in ward to all parts of the muscle via the T-tubule system, D. Begins with an inward movement of K+ ion
C: Spreads in ward to all parts of the muscle via the T-tubule system
Answer: C: Spreads in ward to all parts of the muscle via the T-tubule system 
Explanation: None