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': 'What is p24: \nSelect and explain. \nA. Envelope antigen in HIV, B. Core antigen in HIV, C. Genome of HIV, D. Shell antigen', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b. Core anthigen in HIV', 'role': 'assistant'}]