Final answer:
The Supervisory Appraiser must provide a copy of the requested report to the Trainee.
Step-by-step explanation:
The correct statement regarding this situation is C. The Supervisor must provide a copy of the requested report to the Trainee.
Under the Uniform Standards of Professional Appraisal Practice (USPAP), a Trainee Appraiser is required to sign and retain a copy of any appraisal report they assist in preparing. However, in this situation, the Trainee did not retain a copy of the report. Therefore, the Supervisor must provide a copy to the Trainee upon request.
No other options presented in the question are applicable based on USPAP guidelines.