A12

The correct answer is B. 

This individual has a classic M mode for mitral stenosis, and the most likely clinical finding in this case would be an opening snap. Note on the M mode how the mitral valve fails to open fully in diastole. Compare this to a normally opening mitral valve [insert M mode]. An S3 would be heard in someone with decompensated systolic heart failure and the M mode might show a dilated venticle with large E point septal separation. A murmur that increased with valsalva would been seen in someone with HCM where there might also be SAM. A pericardial knock may be seen in someone with pericarditis which is not diagnosed by M mode although one may be able to see signs of a pericardial effision. A mid systolic click might be heard in someone with MVP which is readily seen by M mode