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: Gynaecology & Obstetrics
[{'content': 'In valvular hea disease complicating pregnancy the following statements are true except : \nSelect and explain. \nA. A closed mitral valvotomy can be carried out if symptoms of mitral stenosis are severe, B. Open hea surgery is associated with a reduction in fetal loss, C. Mitral regurgitation is usually well tolerated, D. A maternal moality of 15% has been repoed in women with critical aoic stenosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Open hea surgery is associated with a reduction in fetal loss', 'role': 'assistant'}]