What type of assignments must have a maintained workfile?

The correct choice focuses on the requirement for a maintained workfile specifically in appraisal and appraisal review assignments. An appraisal workfile is critical because it documents the methods, data, and analyses used to arrive at a value conclusion. Maintaining a workfile ensures transparency and accountability, allowing others to understand the rationale behind the appraiser's decisions.

In appraisal assignments, the workfile includes all relevant data, calculations, and supporting documentation that substantiate the appraised value. In appraisal review assignments, the workfile contains the original appraisal along with the reviewer’s analysis, comments, and conclusions regarding the quality and competency of the initial appraisal. This thorough documentation is vital for quality assurance and compliance with standards.

This requirement stands apart from general consulting assignments, which may not necessitate such formalized documentation, or from review and advisory assignments, where the level of detailed record-keeping can vary based on the nature of the work. Overall, the emphasis on maintaining a workfile in appraisal contexts stems from the need for robust documentation practices that uphold the integrity of the appraisal process.