This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nuclear medicine, Subject name: Radiology
[{'content': 'Parent compound of Tc-99m is \nSelect and explain. \nA. Strontium -99, B. Molybdenum-99, C. Rubidium-99, D. Cs-137', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]