This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiological Study, Subject name: Social & Preventive Medicine
[{'content': 'Incidence of a disease in a population of 30,000 and 300 new cases is? \nSelect and explain. \nA. 0.1 per 1000, B. 10 per 1000, C. 100 per 1000, D. 1 per 1000', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ANSWER: (B) 10 per 1000REF: Park 20th edition page 57Incidence =number of cases of a specific disease during a given period of time Population at risk during that periodx l000In our questionIncidence = 300/30000 x 1000= 10 per thousand', 'role': 'assistant'}]