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': 'Measles is infectious during - \nSelect and explain. \nA. After 4 days of rash, B. 4 days before and 5 days after rash, C. Throughout disease, D. Only in incubation period', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Period of communicability: \n\n\nChickenpox: 1 -\xa02 days before to 4 -\xa05 days after the appearance of the rash\nMeasles: 4 days before to 5 days after the appearance of the rash\nRubella: 7 days before symptoms to 7 days after the appearance of the rash\nMumps: 4 -\xa06 days before symptoms to 7 days thereafter\nInfluenza: 1 -\xa02 days before to 1 -\xa02 days after onset of symptoms\nDiphtheria: 14 -\xa028 days from disease onset\nPertussis: 7 days after exposure to 3 weeks after the paroxysmal stage\nPoliomyelitis: 7 - 10 days before and after the onset of symptoms\nHepatitis A: 2 weeks before to 1 week after onset of jaundice\nHepatitis B: Till disappearance of HBs Ag & appearance of anti-HBs\nMeningococcal: Until absent from nasal and throat discharge\nTuberculosis: As long as not treated', 'role': 'assistant'}]