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: Pathology
[{'content': 'In which of the following locations would you least expect to find significant atherosclerotic lesions in a patient with risky factors of smoking, hypertension, diabetes mellitus, and serum cholesterol level of 280 mg/dl - \nSelect and explain. \nA. Left main coronary artery, B. Aortic bifurcation, C. Circle of Willis, D. Pulmonary artery trunk', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]