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
Which of the following principles of the cavity preparation is not considered much in modern methods of restorative Dentistry? 
Select and explain. 
A. Extension for prevention, B. Convenient form, C. removal of the undermined enamel, D. Removal of the carious dentine
A: Extension for prevention
Answer: A: Extension for prevention 
Explanation: None