In accordance with the ICH GCP Guideline and the CFR, who is directly responsible for...

Theinvestigatoris directly responsible for ensuring that the IRB/IEC reviews and approves the research both initially and on a continuing basis. This responsibility is not delegable to the sponsor or study staff.

ICH E6(R2) 4.4.1:“Before initiating a trial, the investigator/institution should have written and dated approval/favorable opinion from the IRB/IEC for the trial protocol, written informed consent form, consent form updates, and any other written information to be provided to subjects.”

21 CFR 312.66:“An investigator shall assure that an IRB that complies with the requirements… will be responsible for the initial and continuing review and approval of the proposed clinical study.”

This means that while the sponsor submits documents to the FDA and oversees general compliance, theinvestigator has the obligation to obtain and maintain IRB approvalat their site. The monitor or study coordinator may assist in documentation, but legal responsibility rests with the investigator.

Thus, the correct answer isC (The investigator).