If an agent operates outside his duties based on verbal instructions, what power is he using?

The correct choice relates to the type of authority an agent has regarding the instructions they follow. When an agent operates based on verbal instructions, they are exercising what is known as expressed authority. This type of authority is explicitly granted by the principal, and it includes the specific powers that are clearly defined in a contract or through direct communication.

Express authority allows an agent to take actions that are clearly specified, such as making decisions or commitments on behalf of the principal as instructed. In this situation, because the agent is acting specifically based on verbal directives from the principal, it indicates that the agent has the authority to perform the actions communicated through that verbal interaction.

Implied authority, on the other hand, would pertain to actions reasonably expected for an agent to fulfill their duties without explicit instructions each time. Limited authority generally refers to only having certain predefined powers, while inferred authority would suggest powers derived from implied actions rather than clear communication. Hence, operating under verbal instructions directly indicates the use of expressed authority, as it relies on explicit guidance from the principal.