What encompasses the full sum of obligations that ensure an agent acts in the best interest of the client?

The correct choice, fiduciary duties, encompasses the full sum of obligations that ensure an agent acts in the best interest of the client. This concept is rooted in trust and loyalty, where the agent is required to prioritize the client's interests above their own. Fiduciary duties include responsibilities such as the duty of care, which compels the agent to act with competence and diligence, and the duty of loyalty, which mandates that the agent must avoid conflicts of interest and not profit at the client's expense.

Understanding fiduciary duties is crucial in many professional and legal contexts, as these responsibilities create a framework that governs the relationship between agents and clients, ensuring that the client receives fair, ethical, and professional treatment. The enforcement of these duties serves to build trust and maintain the integrity of the professional relationship.