Answer: (D) Interrater reliability.
Step-by-step explanation:
The john and Nina are find interesting in measure of the inter-rater reliability. The inter-rater reliability is also known as inter observer and inter rater agreement.
The inter-rater reliability is the score of the consistency in evaluations given by the similar individual over different examples. The inter and the inter-rater are the reliability of the given test validity. It is one of the test method that assess the external consistency of the given test.
Therefore, Option (D) is correct.