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
Of the following which one correlates with isovolumetric contraction phase 
Select and explain. 
A. AV opening and aortic and pulmonary valve closure, B. AV closure and aortic and pulmonary valve opening, C. Both valves are closed, D. Both valves are open
C: Both valves are closed
Answer: C: Both valves are closed 
Explanation: None