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 is the most potent H2 blocker used in peptic ulcer disease 
Select and explain. 
A. Cimetidine, B. Famotidine, C. Ranitidine, D. Nizatidine
B: Famotidine
Answer: B: Famotidine 
Explanation: Famotidine is the most potent H2 blocker.