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': 'The duration of atrial systole is: \nSelect and explain. \nA. 0.80 second, B. 0.57 second, C. 0.11 second, D. 0.44 second', 'role': 'user'}, {'content': "Answer: C \nExplanation: When the heart beats at a normal rate of 72/minute, duration of each cardiac cycle is about 0.8 second.\xa0\nATRIAL EVENTS\xa0\nAtrial events are divided into two divisions:\xa0\n\nAtrial systole = 0.11 (0.1) sec.\nAtrial diastole = 0.69 (0.7) sec.\xa0\n\nVENTRICULAR EVENTS\xa0\nVentricular events are divided into two divisions:\xa0\n\nVentricular systole = 0.27 (0.3) sec\xa0\nVentricular diastole = 0.53 (0.5) sec.\xa0\n\nIn clinical practice, the term 'systole' refers to ventricular systole and 'diastole' refers to ventricular diastole. Ventricular systole is divided into two subdivisions and ventricular diastole is divided into five subdivisions.", 'role': 'assistant'}]