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': 'Nef gene in HIV is for use - \nSelect and explain. \nA. Enhancing the expression of genes, B. Enhancing viral replication, C. Decreasing viral replication, D. Maturation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Nef gene: Down regulates viral replication', 'role': 'assistant'}]