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: Dental
Incidence is: 
Select and explain. 
A. That portion of population affected by a disease or other condition at a given time, B. Incidence is greater than prevalence, C. No. of new cases of a specific disease within a defined population over a period of time, D. None of the above
C: No. of new cases of a specific disease within a defined population over a period of time
Answer: C: No. of new cases of a specific disease within a defined population over a period of time 
Explanation: None