Which diagram focuses on the flow of data and its processing stages?

The correct choice is the data flow diagram (DFD) because it specifically illustrates how data moves through a system and highlights the processes that transform that data. In a DFD, various components such as data sources, data stores, and processes are represented, emphasizing the flow of information between them. This focus enables stakeholders to understand how data is processed as it moves through different stages of a system.

A data flow diagram does not detail how data is stored or the organizational structure of the system, which makes it distinct from other types of diagrams such as system flowcharts or UML diagrams. System flowcharts concentrate more on procedural flow and the sequence of operations rather than just data flow, while UML diagrams encompass a broad range of aspects of system design, including behavior and structure, rather than focusing solely on data movement. Structure charts emphasize the hierarchical organization of modules in a program, which is unrelated to the data processing stages. Thus, among these options, the data flow diagram is uniquely focused on the flow of data and its processing stages.