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
Profound mitotic delay occurs when the doses are: 
Select and explain. 
A. Smaller, B. Larger, C. Intermediate, D. No effect of doses
B: Larger
Answer: B: Larger 
Explanation: Radiation is especially damaging to rapidly dividing cell systems, such as skin and intestinal mucosa and hematopoietic tissues. Irradiation of such cell populations causes a reduction in size of the irradiated tissue as a result of mitotic delay (inhibition of progression of the cells through the cell cycle) and reproductive cell death (usually during mitosis).
The three mechanisms of reproductive death are:

DNA damage 
Bystander effect
Apoptosis

Note: Large dose of irradiation causes mitotic delay.