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: Medicine
[{'content': 'Y descent in jugular venous pulsation is due to \nSelect and explain. \nA. Ventricular systole, B. Atrial systole, C. Atrial filling, D. Ventricular filling', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Y descent is due to passive movement of blood from atria to ventricles i.e. early diastolic filling', 'role': 'assistant'}]