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': 'What is the duration of a human cardiac cycle in seconds? \nSelect and explain. \nA. 0.4, B. 0.8, C. 1, D. 1.6', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Duration of cardiac cycle (at hea rate of 75/min) is 0.80sec. Out of which duration of systole is 0.27sec and diastole is 0.53sec.', 'role': 'assistant'}]