Of the Following,which Research Design Might Be Considered to Be

Of the following,which research design might be considered to be the best compromise between ecological validity and experimental control?

A) the study of human behavior following a once-in-a-generation natural disaster
B) a study to determine the optimal dosage of a new memory-enhancing drug
C) a study to determine the efficacy of programs to improve workplace efficiency
D) a study to catalogue the range of behaviors of non-human primates in zoos