Informed consent must be obtained from participants before:

The requirement for informed consent as outlined in the Belmont Report emphasizes the ethical principle of respect for persons, which includes the recognition of individual autonomy and the necessity for obtaining voluntary participation in research. Informed consent must indeed be obtained from participants before any research project, regardless of the risk level involved. This principle ensures that all individuals are adequately informed about the nature, risks, and benefits of the research before agreeing to participate, affirming their right to make knowledgeable decisions regarding their involvement.

Informed consent is crucial not only in high-risk studies but also in minimal risk and no risk studies, as it serves to uphold the ethical standards of conducting research. The foundational premise is that participants have the right to understand what they are consenting to, which reinforces their autonomy and fosters trust in the research process. Thus, the correct answer reflects the comprehensive requirement that informed consent is essential for all research projects, thereby ensuring ethical conduct across diverse research contexts.