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: Forensic Medicine
[{'content': 'A man operated for fracture femur developed dyspnea, severe chest pain, streaky hemoptysis and hypotension on 4th day, cause is: UPSC 11; KCET 12 \nSelect and explain. \nA. Air embolism, B. Fat embolism, C. Pulmonary embolism, D. Meningitis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Fat embolism', 'role': 'assistant'}]