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: Pharmacology
Nonsynthetic phase I reaction for drug detoxification is:. 
Select and explain. 
A. Glucuronidation, B. Acetylation, C. Methylation, D. Oxidation
D: Oxidation
Answer: D: Oxidation 
Explanation: None