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': 'Among the natural radiation, the one that contributes to\nmore radiation exposure of general population \nSelect and explain. \nA. Cosmic, B. Terrestrial, C. Radon, D. Consumer products', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The general population is exposed to radiation primarily from natural background and medical sources.\nRadon and its decay products may become attached to dust particles that can be inhaled and deposited on the bronchial epithelium in the respiratory tract. Radon is estimated to be responsible for approximately 73% of the background exposure of the world’s population.\xa0\nKey Concept', 'role': 'assistant'}]