Which of the Following Statements About Compensating Members of Control

Which of the following statements about compensating members of control groups is/are TRUE?

A) Compensation should be provided as soon as possible after people have finished their participation in the research.
B) In the case of psychotherapy research, this compensation usually consists of the psychotherapeutic service that was withheld as part of the re?search.
C) In experimental research, when participants are given a reward as part of a manipulation, members of control groups should be compensated to the same extent.
D) All the above are true.