Study participant recruitment cannot begin until the IRB has approved the:A. Informed Consent form.B. Protocol.C. Advertisements.D. All of the above.

In the context of research involving human participants, obtaining approval from an Institutional Review Board (IRB) is crucial before any recruitment or direct contact with participants can take place. Each component mentioned in the options plays a significant role in ensuring the ethical conduct of the study.

• A. Informed Consent form: This document is necessary to inform participants about the study's purpose, procedures, risks, and benefits. It ensures that participants give their voluntary consent to participate.

• B. Protocol: The study protocol outlines the research design, methodology, participant eligibility, and safety considerations. Approval of the protocol ensures that the study is ethically sound and scientifically valid.

• C. Advertisements: If the recruitment process involves advertising to potential participants, these materials also need IRB approval to ensure they are not misleading and provide appropriate information.

Since all these components must be reviewed and approved for the recruitment process to begin, the correct answer is:

Final Answer

D. All of the above.