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
Which of the following is least radiosensitive? 
Select and explain. 
A. WBC, nerve cells, bone cells, B. RBC, muscle cells, nerve cells, C. Connective tissue cell, endothelial cell, muscle cell, D. Epithelial cell, bone cells, WBC
B: RBC, muscle cells, nerve cells
Answer: B: RBC, muscle cells, nerve cells 
Explanation: None