This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
[{'content': 'Dicrotic notch is due to closure of \nSelect and explain. \nA. Aoic valve, B. Mitral valve, C. pulmonary, D. Tricuspid valve', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Dicrotic notch is due to backflow of blood in the aoa at the beginning of diastole.It marks the end of ventricular systole. Reference:Textbook of medical physiology Geetha,2nd edition,page no:187.', 'role': 'assistant'}]