This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
[{'content': 'The dicrotic notch on the aoic pressure curve is caused by- \nSelect and explain. \nA. Closure of the pulmonary valve, B. Rapid filling of the left ventricle, C. Closure of the aoic valve, D. Contraction of the atria', 'role': 'user'}, {'content': 'Answer: C \nExplanation: dichrotic notch is a small dip in the graph of aoic pressure throughout the cardiaccycle corresponding to the closure of aoic valve Ref Harrison 20th edition pg 1445', 'role': 'assistant'}]