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
In the conventional Class I composite preparation, retention is achieved by which of the following features?
1. Occlusal convergence
2. Occlusal bevel
3. Bonding
4. Retention grooves 
Select and explain. 
A. 2 and 4, B. 1 and 3, C. 1 and 4, D. 2 and 3
B: 1 and 3
Answer: B: 1 and 3 
Explanation: Typically, the Class I composite preparation has occlusally converging walls that provide primary retention form. The actual bonding also provides retention form. However, an occlusal bevel is not indicated on Class I preparations nor are retention grooves used.