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: Pathology
Cells are most radiosensitive in: 
Select and explain. 
A. S-phase, B. M-phase, C. G1-phase, D. G0–phase
B: M-phase
Answer: B: M-phase 
Explanation: Cells are most radiosensitive in G2-M interphase.
Cells are least radiosensitive in S phase.