Suppose That After the Study Described in #5 We Want

Suppose that after the study described in #5 we want to see if there's evidence that the exercise program's effectiveness in lowering blood pressure depends on how high the person's initial blood pressure was. We should do a

A) ç² test of independence
B) ç² goodness-of-fit test
C) matched pairs t-test
D) linear regression t-test
E) 2-sample t-test