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
Sensitivity in gingival area of class II light cured composite restoration after 2 months is due to: 
Select and explain. 
A. Improper cavity preparation at gingival margin, B. Curing from occlusal area only, C. Addition of resin in multiple increments, D. Curing from buccal and lingual aspect
A: Improper cavity preparation at gingival margin
Answer: A: Improper cavity preparation at gingival margin 
Explanation: None