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
The penetration of the fissure sealant into the fissure: 
Select and explain. 
A. Is not influenced by the wettability of the enamel, B. Is independent of the chemical composition of the enamel, C. Is the result of a chemical bond between the sealant and enamel, D. Must occur before the polymerization of the material
D: Must occur before the polymerization of the material
Answer: D: Must occur before the polymerization of the material 
Explanation: None