If a Research Question Requires the Researcher to Induce Stress

If a research question requires the researcher to induce stress in participants:

A) the research cannot be conducted.
B) at the end of the study, the researcher must return participants to same or better physical and psychological state.
C) researchers must ensure the presence of residual stress after the research study.
D) it is fine as long as the researcher believes the benefits outweigh the costs.