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: Dental
Possible contra indications for periapical surgery are 
Select and explain. 
A. Controlled diabetis mellitus, B. The danger of damage to adjacent structures, C. A history of rheumatic fever, D. Congenital heart disease
B: The danger of damage to adjacent structures
Answer: B: The danger of damage to adjacent structures 
Explanation: None