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': 'Most efficient anti\xadlarval measure to prevent urban malaria is \nSelect and explain. \nA. Clean drainage and sewerage systems, B. Cover overhead tanks properly, C. Filling cesspools and ditches, D. Cover pits', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In urban areas, Malaria is mainly transmitted by Anopheles stephensi.\nRecommended measures for Urban Malaria contro l: Breeds in man-made water containers in domestic / peridomestic situations such as tanks, wells, cisterns, which are of permanent nature and hence can malaria transmission throughout the year.\nMeasures for Urban Malaria Control:\n\nLids of overhead tanks must be checked and maintained monthly basis; any leakage be repaired immediately (most effective).\nCover-up of underground and open tanks.\nOpen tanks used for animals be dead dried once in week Never to throw any containers in open capable of holding water.\nConstruction sites: Building bye-laws be implemented to prevent fault in designs, water flow on roof, gully traps open tanks for curing be treated with larvicides on weekly basis.\nUnused wells either be closed or treated with larvicides Ornamental tanks, fountains be checked periodically and larvivorous fish be introduced\nPublic health engineers be involved for proper drainage, building designs, periodic flushing of water logged areas and drainage.', 'role': 'assistant'}]