This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable Diseases, Subject name: Social & Preventive Medicine
[{'content': 'Preservative added in DPT vaccine is : \nSelect and explain. \nA. Zinc phosphate, B. Aluminum phosphate, C. MgS04, D. ZnS04', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e. Aluminium Phosphate Aluminium phosphate is used as an adsorbent in DPT vaccine. Adsorption increases the immunological effectiveness of the vaccine", 'role': 'assistant'}]