Final answer:
The duty described is the duty of confidentiality which is fundamental in any agency relationship, requiring agents to keep information that may harm their principal's bargaining position confidential.
Step-by-step explanation:
The correct answer to the student's question is: a) Confidentiality.
In the context of fiduciary duty within agency relationships, the duty of confidentiality is paramount. This duty requires that an agent must not disclose or use any information for their own benefit or anyone else's if it is likely to be detrimental to the principal’s interests or bargaining position. The duty stays in place not only for the duration of the agency relationship but also after its termination.
It encompasses a wide array of information that could include trade secrets, customer lists, and any inside information that the agent has gained as a result of their position. Violating this duty can lead to legal consequences and a loss of trust which is the foundation of the principal-agent relationship.