What of the Following Is an Obligation That Researchers Have

What of the following is an obligation that researchers have with study participants?

A) Provide a financial incentive to participate in the study.
B) Provide free treatment for any condition the subjects have.
C) Communicate the study results clearly.
D) Enroll all family members of the participants if they want to be part of the study.
E) Provide free diagnostic procedures, even if those are not related with the study.