This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Medicine
[{'content': 'Meningitis bacteria are normally present in? \nSelect and explain. \nA. Nasopharynx, B. Skin, C. Genitals, D. Lower G.I.T', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. (a) NasopharynxRef: Harrison's 19th ed. / 997, 999* The natural habitat and reservoir for meningococci is the mucosal surfaces of the human nasopharynx and, to a lesser extent, the urogenital tract and anal canal.* Approximately 5-10% of adults are asymptomatic nasopharyngeal carriers, but that number increases to as many as 60-80% of members of closed populations (e.g, military recruits in camps).* The modes of infection include direct contact or respiratory droplets from the nose and throat of infected people.* The incubation period averages 3-4 days (range 1-10 days), which is the period of communicability.* Bacteria can be found for 2-4 days in the nose and pharynx and for up to 24 hours after starting antibiotics", 'role': 'assistant'}]