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': 'In antacid preparation aluminum hydroxide is added with magnesium salt because - \nSelect and explain. \nA. Magnesium caused constipation, B. To counteracts constipating effect of aluminum hydroxide, C. To counteract the diarrhea action of aluminum, D. Aluminum salt causes diarrhea', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans is 'b' i.e., To counteracts constipating effect of aluminum hydroxide o Magnesium salts are laxative and aluminium salts are constipating and the combination of both salts neutralises each other's action and bowel movement may be least affected.", 'role': 'assistant'}]