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
Most common phase I biotransformation reaction is? 
Select and explain. 
A. Oxidation, B. Hydrolysis, C. Cyclisation, D. Reduction
A: Oxidation
Answer: A: Oxidation 
Explanation: Ans. is 'a' i.e., Oxidation Oxidation is the most impoant metabolizing reaction.