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': 'A 40-year old female presented with dyspnoea on exeion grade III and palpitations. ECG showed atrial fibrillation with fast ventricular rate. Echocardiography shows severe mitral stenosis with left atrial appendage clot. Which of the following is not advised? \nSelect and explain. \nA. Diltiazen to control ventricular rate, B. Sta warfarin and follow-up with repeat echocardiography, C. EC followed by percutaneous balloon mitral valvuloplasty, D. Open mitral commissurotomy with clot removal', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. c. EC followed by percutaneous balloon mitral valvuloplasty', 'role': 'assistant'}]