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
Radiation caries appears in: 
Select and explain. 
A. 3 weeks, B. 6 months, C. 3 months, D. 6 weeks
C: 3 months
Answer: C: 3 months 
Explanation: None