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': '–30°– 60° left axis deviation – \nSelect and explain. \nA. Left ventricular hypertrophy, B. Right ventricular hypertrophy, C. Aortic stenosis, D. Left atrial enlargement.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]