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 of these cells is most radio-resistant? \nSelect and explain. \nA. Early precursor cells of erythroblastic series, B. Muscle cells, C. Fibroblasts, D. Vascular endothelial cells', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]