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 region of myocardium most prone for infarction is: \nSelect and explain. \nA. Rt. ventricular epicardial, B. Lft. ventricular epicardial, C. Rt. Ventricular sub endocardial, D. Lft. Ventricular sub endocardial', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]