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': 'Pressure-Volume loop of cardiac cycle is shown below. What does point C represent? \nSelect and explain. \nA. Mitral valve opens, B. Mitral valve closes, C. Aortic valve opens, D. Aortic valve closes', 'role': 'user'}, {'content': 'Answer: C \nExplanation: At point C, Ventricular pressure becomes more than aortic pressure. Hence, aortic valve opens.', 'role': 'assistant'}]