Answer:
The correct answer is c. matched-groups
Step-by-step explanation:
The kind of design Kathryn is using is matched groups.
Matched groups design refers to a technique in research design in which a participant in an experimental group being exposed to a manipulation is compared on an outcome variable to a specific participant in the control group who is similar in some important way but did not receive the manipulation for instance Kathryn wants to control for intelligence in her study, She has a list of all of the participants for her study and their IQ scores, She sorts the list of participants according to their IQ scores and then forms groups making sure that the groups are balanced in terms of IQ scores, Finally, she randomly assigns each group to one of the conditions of her study.