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
[{'content': 'The MOST common cause of tricuspid regurgitation is secondary to: \nSelect and explain. \nA. Rheumatic hea disease, B. Dilatation of right ventricle, C. Coronary aery disease, D. Endocarditis due to intravenous drug abuse', 'role': 'user'}, {'content': 'Answer: B \nExplanation: All mentioned condition are causes of tricuspid regurgitation. Most commonly, TR is secondary to marked dilation of the tricuspid annulus from RV enlargement due to PA hypeension. Ref: Harrisons principles of internal medicine, 18th edition, Page 1948.', 'role': 'assistant'}]