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
[{'content': 'Which of the following inhibits the rate limiting step in synthesis of epinephrine ? \nSelect and explain. \nA. Guanithidine, B. Bretylium, C. Metyrosine, D. Peserpine', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Metyrosine", 'role': 'assistant'}]