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: Social & Preventive Medicine
[{'content': 'Chandlers Index is used in epidemiological studies of: \nSelect and explain. \nA. Round worm, B. Hook worm, C. Guinea worm, D. Sand fly', 'role': 'user'}, {'content': "Answer: B \nExplanation: Chandler's index is used to identify the impoance of hookworm infestation as a public health problem in a community. It is calculated based on average number of hookworm eggs / gram of stool. Average no. of hookworm eggs/gm of stool Significance of hookworm infestation <200 Not much significance 200-250 Potential danger 250-300 Minor public health problem >300 Major public health problem Ref: Park's textbook of Preventive and Social Medicine, 21st edition, page-221", 'role': 'assistant'}]