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': 'All the heart valves are open during which stage of cardiac cycle: \nSelect and explain. \nA. Systolic ejection, B. Isovolumetric relaxation, C. Isovolumetric contraction, D. None of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]