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
Drugs undergoing acetylation include all except - 
Select and explain. 
A. Dapsone, B. Metoclopramide, C. Procainamide, D. INH
B: Metoclopramide
Answer: B: Metoclopramide 
Explanation: Ans. is 'b' i.e., Metoclopramide Drugs metabolized by acetylation o Sulfonamides (including dapson) o Procainamide o PAS o INH o Hydralazine o Clonazepam