Dr Soto Was Conducting Research in a Small Rural Community

Dr. Soto was conducting research in a small rural community in Asia that was affected by an earthquake. Dr. Soto collected baseline measurements on posttraumatic responses and then the natural disaster assistance team arrived. Dr. Soto collected the same information again from respondents after the disaster assistance team had been stationed for one week. After two weeks the disaster assistance team left and Dr. Soto collected posttraumatic response data again. Dr. Soto expected that the posttraumatic responses would return to baseline after the disaster assistance team left. Dr. Soto is using which type of design?

A) hybrid design
B) factorial design
C) A-B design
D) A-B-A