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 isovolumic contraction phase 
Select and explain. 
A. AV opening and aortic and pulmonary valve closure, B. AV closure and aortic & 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: ‘Isovolumetric’ means the volume remains same. That occurs only when both the valves are closed.