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': 'True about active immunity - \nSelect and explain. \nA. Less effective, B. Can be given in immunodeficient state, C. Immunological memory present, D. No lag period', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]