Final answer:
A profession, according to the power approach, is best described by the authority and control it exerts in a field, reflecting the sociological insights on power by Max Weber.
Step-by-step explanation:
From the power approach method of defining a profession, the best description is that a profession is characterized by the level of authority and control it holds within a specific field. This aligns with the sociological understandings of power as described by Max Weber, who identified power as the ability to exercise one's will over others and noted that power is an integral part of social structures including professions.
The functionality of professions, as seen through the power approach, does not primarily focus on financial benefits, required education, or ethical standards, but rather on the power dynamics that give a profession its status and influence within a society.