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: Radiology
[{'content': 'USG wave travel in the human body at the rate of – \nSelect and explain. \nA. 1500 m/s, B. 2500 m/s, C. 3500 m/s, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Speed of sound wave in body is 1540 m/s.', 'role': 'assistant'}]