In Colorado, a Single Agent relationship requires:

Option A is incorrect because Colorado law specifically mandates written documentation for Single Agent relationships. Verbal agreements are insufficient to establish this type of agency relationship, as they fail to provide the clarity and legal protection required by state regulations.

Option C is incorrect because verbal consent alone is not sufficient to establish a Single Agent relationship in Colorado. While verbal agreements may be valid in other contexts, state law requires written documentation for this specific agency relationship to ensure clarity and enforceability.

Option D is incorrect because commission approval is not a requirement for establishing a Single Agent relationship in Colorado. This option represents a misunderstanding of agency formation, which is governed by the brokerage agreement between the broker and client, not by regulatory bodies.