This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'Immunity by vaccine is- \nSelect and explain. \nA. Active natural, B. Passive natural, C. Active acquired, D. Passive acquired', 'role': 'user'}, {'content': 'Answer: C \nExplanation: .vaccine is an immunobiological substance designed to produce specific protection against a given disease.it stimulates the production of protctive antibody and other immune mechanisms.it can be prepared from live modified organisms,inactivated or killed organisms,extracted cellular fractions,toxoids,or combination of these.hence vaccines induces active acquired immunity. ref:park&;s textbook,22 nd ed,pg 99', 'role': 'assistant'}]