Which of the Following Is NOT a Disadvantage of the Case

Which of the following is NOT a disadvantage of the case study method?

A) It is hard to detect or control all important variables acting in a given case.
B) Data or conclusions from an individual case may not apply to people in general.
C) Case studies do not allow us to draw conclusions about cause and effect.
D) Case studies are unethical because they involve the disclosure of confidential information.