Which diagram is least suited for representing system and context delimitation?

A state diagram is primarily used to represent the behavior of a system over time, capturing the states an object can be in and the transitions between those states based on events. This type of diagram focuses on dynamic aspects of system behavior rather than the structural aspects or the boundaries of the system in relation to its environment.

In contrast, a context diagram with data flows offers a clear representation of the system and its interactions with external entities, emphasizing the boundaries of the system and what lies inside versus outside those boundaries. Use case diagrams also provide a good representation of system boundaries by illustrating the interactions between users (actors) and the system. Class diagrams, while useful for showing the static structure of a system, do not inherently provide context delimitation, but can still help to outline the components involved.

Therefore, among the options provided, the state diagram is the least suited for representing system and context delimitation since it does not convey the external interactions or boundaries of the system effectively.