This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
[{'content': 'Left anterior descending artery is a branch of: \nSelect and explain. \nA. Right coronary artery, B. Left coronary artery, C. Ascending aorta, D. Coronary sinus', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. B Left coronary arteryRef: Gray's Anatomy Review E-book, P 80Left anterior descending artery is a branch of left coronary artery.", 'role': 'assistant'}]