In use case terminology, a primary actor is defined as:

In use case terminology, a primary actor is defined as:

• A. A person
• B. An external system
• C. A person or external system that interfaces with your system
• D. A data structure

Answer: (C)

In use case modeling, actors are the roles outside the system that interact with it. The primary actor is the one who initiates the use case to achieve a goal with the system. That role can be a person or another system that interfaces with your system. So describing a primary actor as a person or external system that interfaces with your system captures both ways the system can be driven: by a user directly or by another system that starts the interaction. A data structure isn’t an actor—it's part of the system’s inside data or design, not an external role that interacts with the system. And limiting the idea to only a person misses the possibility that another system can also start the use case and seek the system’s help to reach a goal.

In use case modeling, actors are the roles outside the system that interact with it. The primary actor is the one who initiates the use case to achieve a goal with the system. That role can be a person or another system that interfaces with your system. So describing a primary actor as a person or external system that interfaces with your system captures both ways the system can be driven: by a user directly or by another system that starts the interaction.

A data structure isn’t an actor—it's part of the system’s inside data or design, not an external role that interacts with the system. And limiting the idea to only a person misses the possibility that another system can also start the use case and seek the system’s help to reach a goal.