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
The phase of cell cycle, most sensitive to radiation isa) M Phase  b) G2Phase  c) S Phase  d) Early G1 Phase e) G0Phase 
Select and explain. 
A. ac, B. ab, C. de, D. cd
B: ab
Answer: B: ab 
Explanation: Cells are most radiosensitive in late G, and early M phase → especially G2M interphase.