Answer:b) Criterion validity.
Step-by-step explanation:
Criterion validity is defined as the scale or level to which a measure is associated with the result .It can predict the result of a particular measure using some other measure for defining the performance and validity.
According to the question,Shakendra is taking help of criterion validity for explaining about the GRE test through the aspect of GPA test of the graduate school.
Other options are incorrect because content validity is used for knowing about the intention extent of the test measure. Discriminant validity is measure till components are different .Convergent validity is used social and behavior field .
Thus, the correct option is option(b).