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': 'The number of new cases occurring in a defined population during a specified period of time is called - \nSelect and explain. \nA. Period prevalence, B. Point prevalence, C. Prevalence, D. Incidence', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]