This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Pharmacology
Which of the following is not an example of Phase II drug metabolic reaction? 
Select and explain. 
A. Acetylation, B. Sulfation, C. Decyclization, D. Methylation
C: Decyclization
Answer: C: Decyclization 
Explanation: phase 1 reactions- oxidation, reduction, cyclization, decyclization and hydrolysis Phase II reactions: 1. Glucuronidation 2. Acetylation 3. Glutathione conjugation 4. Glycine conjugation 5. Sulfation 6. Methylation 7. Water conjugation Reference: Katzung Pharmacology; 13th edition; Chapter 4; Drug Biotransformation