Final answer:
Option (A), The instructor should inform the student nurse that students are not allowed to witness legal documents like consent forms and should clarify this with the staff nurse.
Step-by-step explanation:
The best response by the instructor to a student nurse being asked to witness a surgical consent form after the surgeon signs it would be option A: "Students are not to serve as a witness to legal papers. Let's explain this to the staff nurse so they may have it witnessed." This policy is in place because witnessing a consent form is a legal responsibility that requires an understanding of the consent process and the capability to testify that the person signing the consent did so voluntarily and was competent to do so. A student nurse typically does not yet have the legal authority or the professional capacity to undertake this responsibility.