For which of the following reasons may an agent's authority legally expand in emergencies?

An agent's authority may legally expand in emergencies primarily to address unforeseen situations. This principle is rooted in the need for quick and decisive action when circumstances arise that the agent was not able to anticipate. In an emergency, the agent may need to take actions that go beyond their normal scope of authority to protect the principal's interests, preserve property, or respond to crises effectively.

When an unforeseen event occurs, such as a natural disaster or a sudden market change, the agent must have the flexibility to act without waiting for the principal’s specific instructions, which may not be possible in the moment. This expanded authority is justified because the principal would want the agent to act in a way that prevents harm or loss during such critical times.

The other choices do not align as directly with the legal principles governing agency. While protecting the principal's interests is certainly a goal of agency relationships, it is the specific need to respond to unforeseen situations during an emergency that legally justifies an expansion of authority. Typical business operations and an increase in the agent’s role do not inherently create the same urgent need for expanded authority in emergencies.