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': 'Which element of the following on disintegration leads to daughter element in gaseous form? \nSelect and explain. \nA. Radium, B. Iridium, C. Radon, D. Uranium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: As radium decays or disintegrates, it forms Radon gas (earth’s only naturally produced radioactive gas),\nwhich can enter homes, buildings, and wells and if not ventilated may cause Radiation sickness.', 'role': 'assistant'}]