This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'Endemic disease is defined as a disease- \nSelect and explain. \nA. Occurance regularly in expected frequency, B. Occurance irregularly from time to time, C. Occurance in excess of expected frequency, D. Occurance in large population', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Occurance regularly in expected frequency * Sporadic - Disease occuring irregularly from time to time.* Endemic - Disease occuring regularly in expected frequency.* Epidemic - Disease occuring in excess of expected frequency.* Pandemic - Epidemic affecting a large proportion of population over a wide geographic area.", 'role': 'assistant'}]