This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
[{'content': 'Sputum examination for AFB is a type of \nSelect and explain. \nA. Primary prevention, B. Secondary prevention, C. Teiary prevention, D. Primordial prevention', 'role': 'user'}, {'content': "Answer: B \nExplanation: Sputum AFB is a diagnostic test intended for the early diagnosis and adequate treatment. Secondary prevention: an action which halts the progress of the disease at its incipient stage and prevents complications. The interventions include early diagnosis and treatment. Ref: Park's Textbook of Preventive and Social Medicine; 24th edition - Page no. 46", 'role': 'assistant'}]