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
The dicrotic notch on the aoic pressure curve is caused by- 
Select and explain. 
A. Closure of the pulmonary valve, B. Rapid filling of the left ventricle, C. Closure of the aoic valve, D. Contraction of the atria
C: Closure of the aoic valve
Answer: C: Closure of the aoic valve 
Explanation: 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