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
What is the major difference between a class V cavity preparation for amalgam and one for composite resin by the acid-etch technique? 
Select and explain. 
A. Depth, B. Convenience form, C. Position of retentive points, D. Angulation of enamel cavosurface margins
D: Angulation of enamel cavosurface margins
Answer: D: Angulation of enamel cavosurface margins 
Explanation: None