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: Microbiology
[{'content': 'Which of the following is most potent antigen for stimulating both humoral and cell mediated immunity? \nSelect and explain. \nA. Adjuvant, B. Proteins, C. Polysaccharides, D. Lipids', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]