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': 'Which of the following constitutes secondary prevention \nSelect and explain. \nA. Health education programmes, B. Wearing safety helmets, C. Using limb calipers, D. Screening test', 'role': 'user'}, {'content': "Answer: D \nExplanation: Secondary prevention includes early detection ( diagnostic tests and screening tests) and treatment. Ref: Park's textbook of preventive and social medicine; 23rd edition; Page no 42", 'role': 'assistant'}]