Answer:
There answer is C.
Step-by-step explanation:
Explanatory variables are independent variables meaning they are not affected by the other variables in the equation. Response variable are dependent variables meaning their results depend on the direction of the other variable(s).
The correct answer is C, college GPA is the response variable because it defines the groups to be compared with respect to the values of high school gpa, and it is dependent on the high shcool gpa results. Therefore high school gpa is the explanatory variable.
I hope this answer helps.