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
Which of the following inhibits the rate limiting step in synthesis of epinephrine ? 
Select and explain. 
A. Guanithidine, B. Bretylium, C. Metyrosine, D. Peserpine
C: Metyrosine
Answer: C: Metyrosine 
Explanation: Ans. is 'c' i.e., Metyrosine