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
All the drugs given below can be used to protect gastric ulcer except 
Select and explain. 
A. Colloidal bismuth salt, B. Magnesium hydroxide, C. Misoprostal, D. Sucralfate
B: Magnesium hydroxide
Answer: B: Magnesium hydroxide 
Explanation: None