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
Dose of radiation which leads to mucositis is: 
Select and explain. 
A. 1000 rads., B. 1500-2000 rads., C. 2500-3000 rads., D. 3500-4000rads.
D: 3500-4000rads.
Answer: D: 3500-4000rads. 
Explanation: None