Which UML diagram is typically used for showing the static structure of a system?

A Class Diagram is the correct choice for illustrating the static structure of a system because it effectively represents the system's classes, their attributes, methods, and the relationships between the classes. This type of diagram provides a comprehensive view of how different components of a system interact with one another at a structural level, making it easy to understand the overall design and organization.

Class Diagrams are fundamental in object-oriented design as they highlight key concepts such as encapsulation, inheritance, and polymorphism, which are essential for modeling software applications. In contrast, other types of UML diagrams serve different purposes:

Activity Diagrams focus on the flow of activities and processes, highlighting the dynamic behavior of a system rather than its static aspects. Sequence Diagrams detail the interactions between objects over time, emphasizing the order of messages exchanged, which again differs from the static structural representation. Use Case Diagrams illustrate the functional requirements of a system from an external perspective, capturing the interactions between users (actors) and the system without detailing the internal structure.

Thus, the Class Diagram is uniquely suited for depicting the static structure, making it an essential tool in system design and analysis.