What Is the Primary Reason a Researcher Might Not Use

What is the primary reason a researcher might not use the experimental research design?

A) Many topics can not be explored ethically with the experimental research design
B) The design does not provide any information about causality
C) Because these studies are across time (e.g., one year or two year follow-up) , they take too long to complete
D) The design is looked down upon by the field of developmental psychopathology