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
Water tree phenomenon is shown by: 
Select and explain. 
A. 4th generation DBA, B. 5th generation DBA, C. 6th generation DBA, D. 7th generation DBA
D: 7th generation DBA
Answer: D: 7th generation DBA 
Explanation: It's a microscopic appearance in cured layer of dentin adhesive due to incomplete water evaporation seen in 7th generation bonding agents.