This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical Illness Complicating Pregnancy, Subject name: Gynaecology & Obstetrics
[{'content': 'A pregnant woman with Mitral stenosis is likely to undergo failure in the antenatal period. Best results to prevent Failure with severe stenosis is the following \nSelect and explain. \nA. T. Furosemide through out pregnancy, B. Balloon mitral valvotomy in second trimester, C. Digoxin for all hea patients, D. Admit all at 30 weeks', 'role': 'user'}, {'content': 'Answer: B \nExplanation: For Best results to prevent Failure with severe Mitral stenosis, Balloon mitral valvotomy is preferred treatment. Balloon mitral valvotomy is usually done in Second trimester,the ideal time being 20 weeks', 'role': 'assistant'}]