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: Microbiology
[{'content': 'The following statements about meningococcal meningitis are true except \nSelect and explain. \nA. The source of infection is mainly clinical case, B. The disease is more common in dry and cold months of the year, C. Chemoprophylaxis of close contacts of cases is recommended, D. The vaccine is not effective in children below 2 yrs of age', 'role': 'user'}, {'content': "Answer: A \nExplanation: The human nasopharynx is the only reservoir of the Meningococcus. Asymptomatic nasopharyngeal carriers rarely contract the illness but serve to infect their contacts Transmission is essentially by airborne droplets or less often by fomites. So the best specimen to be collected for Neisseria meningitidis is nasopharyngeal swab. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 232", 'role': 'assistant'}]