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': 'Pulmonary embolism is most commonly produced by which of the following - \nSelect and explain. \nA. Trauma, B. Atherosclerosis, C. Thrombosis of pelvic vessels, D. None', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]