This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
True in mitral regurgitation (MR) is 
Select and explain. 
A. Pansystolic murmur at the apex, B. Loud S1, C. Functional or Secondary MR is caused by papillary muscle rupture after myocardial infarction, D. ECG commonly reveals 'P' pulmonale
A: Pansystolic murmur at the apex
Answer: A: Pansystolic murmur at the apex 
Explanation: S1 is soft in MR unlike MS. 
Functional or Secondary MR is caused by dilation of the left ventricle causing leakage at the mitral annulus. 
ECG in MR shows 'P' mitrale due to dilation of the Left atrium.