Ingrid works as a teacher in a small private school that does not have a food service program. She sees what kids bring to school and is very worried that families are not supporting their children's nutritional needs enough. This year she decides to conduct a study to see if sending home literature and homework that parents must do with their children makes a difference in their application of appropriate selections in children's lunches at the end of the year. Which of the following designs best represents Ingrid's research design plan?

Group of answer choices

a. One-group posttest-only design

b. Solomon four-group design

c. Pretest-post-test control group

d. Posttest-only design with non-equivalent groups