What term describes a person who has a special relationship of trust and responsibility in an agency relationship?

The term that best describes a person who has a special relationship of trust and responsibility in an agency relationship is "fiduciary." A fiduciary is someone who acts on behalf of another party, typically in financial or legal matters, and is expected to act in the best interest of that party. This relationship is characterized by a high degree of trust and confidence and encompasses duties such as loyalty, full disclosure, and the avoidance of conflicts of interest.

While "agent" refers to an individual authorized to act on behalf of another in dealings with third parties, it does not inherently include the significance of the trust and responsibility found in a fiduciary relationship. The term "trustee" typically refers to someone who manages property or assets for the benefit of another, usually within the confines of a trust agreement, but does not capture the broader role of fiduciary duty present in various agency relationships.

Therefore, while all these terms relate to relationships that involve responsibility and trust, "fiduciary" specifically embodies the essence of a special relationship built on trust and responsibility, which is fundamental to the agency relationship. Thus, while "all of the above" might seem inclusive, it doesn't highlight the specific nuance that fiduciary accurately conveys in the context of an agency relationship.