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
Objective of calibrating examiner before survey is to: 
Select and explain. 
A. Ensure uniform interpretation, understanding and application of diagnostic criteria, B. Measure consistently at different times and under a variety of conditions, C. Reduce intra- and inter examiner reliability, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: None