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
Reliability is tested by 
Select and explain. 
A. R-chart, B. Mean chart, C. Levy Jennings chart, D. Shewhart control chart
A: R-chart
Answer: A: R-chart 
Explanation: None