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
Prevalence is a: September 2007 
Select and explain. 
A. Rate, B. Ratio, C. Propoion, D. Percentage
C: Propoion
Answer: C: Propoion 
Explanation: Ans. C: Propoion