An Educator Is Interested in Whether Including a Physically Challenged

An educator is interested in whether including a physically challenged student in a kindergarten class will enhance the other students' level of compassion. The educator assesses the students' level of compassion at the beginning of the year, before the physically challenged student was assigned to the classroom. At the end of the school year, the educator reassesses the students' level of compassion and notes whether overall compassion has increased or decreased. This is an example of which type of research design according to Campbell and his colleagues?

A) the posttest-only control group design
B) the one-shot case study design
C) an expectancy control design
D) the one-group pre-post study