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
Improved marginal adaptation in a composite restoration can be achieved by: 
Select and explain. 
A. Moisture free environment, B. Application of pressure, C. Acid etching, D. Continued packing
C: Acid etching
Answer: C: Acid etching 
Explanation: None