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: Radium REF: Encyclopedia of environmental science - page 299 As radium decays or disintegrates, it forms Radon gas (eah's only naturally produced radioactive gas), which can enter homes, buildings, and wells and if not ventilated may cause Radiation sickness.", 'role': 'assistant'}]