This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacokinetics, Subject name: Pharmacology
Which of the following is an example of a phase 1 Xenobiotic reaction? (Repeat) 
Select and explain. 
A. Acetylation, B. Hydroxylation, C. Methylation, D. Glucuronidation
B: Hydroxylation
Answer: B: Hydroxylation 
Explanation: Ans: B (Hydroxylation) Ref: The Pharmacological basis of therapeutics by Goodman & Gilman - 12th ed, page no. 125Explanation:Hydroxylation is an example for phase 1 reaction while.Acetylation, glucuronidation and methylation are examples of conjugation reactions which are phase 2 reactions. (See Table 7)