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
[{'content': 'Most common phase I biotransformation reaction is- \nSelect and explain. \nA. Oxidation, B. Hydrolysis, C. Cyclisation, D. Reduction', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Oxidation o Oxidation is the most important metabolizing reaction.", 'role': 'assistant'}]