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
In a village having population of 1000, we found patients with certain disease. The results of a new diagnostic test on that disease are also follows -What is the percent prevalence of disease - 
Select and explain. 
A. 0.2, B. 2, C. 18, D. 20
D: 20
Answer: D: 20 
Explanation: Prevalence is defined as all current cases (old + new) at a given point of time