Which type of diagram is a compositional hierarchy?

A compositional hierarchy is best represented by a structural diagram because it visually illustrates the arrangement and relationships of various components within a system. This type of diagram focuses on how components are composed and organized, showcasing how smaller parts combine to form larger units. It emphasizes the hierarchical nature of the system, often used in engineering to depict the physical structure of a system or its components.

Structural diagrams are instrumental in breaking down complex systems into simpler, more manageable parts, which helps in understanding the interrelationships and dependencies between these parts. This clarity is crucial in engineering practices where understanding the system's organization can impact design and function.

The other diagram types have distinct characteristics: relational diagrams focus on relationships between entities rather than composition, block diagrams generally represent systems' functional aspects without the details of the structure, and classification diagrams categorize entities based on shared attributes rather than highlighting their hierarchical composition. Therefore, a structural diagram is the most suitable choice for depicting a compositional hierarchy.