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
All of the following murmurs may be heard in patients with aoic reugurgitation except - 
Select and explain. 
A. High-pitched decrescendo diastolic murmur, B. Soft, low pitched middiastolic rumbling murmur, C. Mid-systolic ejection flow murmur, D. Presystolic murmur
D: Presystolic murmur
Answer: D: Presystolic murmur 
Explanation: S 1 is generally absent, soft, or buried in the holosystolic murmur of chronic MR. A low-pitched S 3 occurring 0.12-0.17 s after the aoic valve closure sound,It may be followed by a sho, rumbling, mid-diastolic murmur, even in the absence of structural MS. A presystolic murmur is not ordinarily heard with isolated MR. A systolic murmur of at least grade III/VI intensity is the most characteristic auscultatory finding in chronic severe MR. It is usually holosystolic, but as previously noted it is decrescendo and ceases in mid- to late systole in patients with acute severe MR. ( Harrison&;s principle of internal medicine,18th edition,pg no. 1935)