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
[{'content': 'Of the following which one correlates with isovolumic contraction phase \nSelect and explain. \nA. 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', 'role': 'user'}, {'content': 'Answer: C \nExplanation: ‘Isovolumetric’ means the volume remains same. That occurs only when both the valves are closed.', 'role': 'assistant'}]