Final answer:
The 15-hour National USPAP Course or equivalent is the required USPAP course for becoming a Trainee Appraiser.
Step-by-step explanation:
The required USPAP course as a prerequisite to becoming a Trainee Appraiser is the 15-hour National USPAP Course or equivalent. This course provides the trainee with a comprehensive understanding of the Uniform Standards of Professional Appraisal Practice (USPAP) and covers topics such as ethical considerations, competency, scope of work, and reporting requirements for appraisers.