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
Some times the following diastolic sounds heard during cardiac auscullation- 
Select and explain. 
A. S3, B. S4, C. Opening snap, D. Ejection click
A: S3
Answer: A: S3 
Explanation: The third hea sound (S3) is a low-pitched, early diastolic sound audible during the rapid entry of blood from the atrium to the ventricle. When arising from the LV, it is best audible at the apex with the patient in left lateral decubitus position with breath held at end expiration Ref Harrison 20th edition pg 1545