A therapist wants to understand if there is an interaction of medication type and therapy type to treat generalized anxiety disorder. She randomly assignments 40 patients to receive either Drug A or Drug B, and to participate in cognitive behavioral therapy (CBT) or psychoanalytic therapy. Patients anxiety scores are reported. Based on the SPSS output, do you need a Tukey for drug type? Why or why not?

a) No; there is not a significant difference between drug types

b) Yes; there is not a significant difference between drug types

c) Yes; there is a significant difference between drug types and there are more than two groups

d) No; while there is a significant difference between drug types, there are only two groups