A factorial study compares the effectiveness of two allergy medications by measuring symptoms immediately before taking the medication, 30 minutes after the medication, and 3 hours after the medication. Half of the participants take one of the medications and the rest take the second medication. Which statement accurately describes this study?

a. It is a between-subjects design that uses both the experimental and non-experimental strategies.
b. It is a between-subjects experiment.
c. It is a non-experimental between-subjects design.
d. It combines between- and within-subjects designs and uses both the experimental and non-experimental strategies