What tool is used to illustrate the movement of information within a system?

The Data Flow Diagram (DFD) is specifically designed to illustrate the movement of information within a system. It visually represents how data is transmitted between processes, data stores, and external entities. This makes it an effective tool for analyzing and understanding a system's information flow, highlighting the inputs and outputs of various processes and how they interact with one another.

DFDs use specific symbols to denote processes, data stores, and flows of information, making them distinct and clear in conveying how data moves through a system. This clarity helps stakeholders grasp the dynamics of data management and serves as a blueprint for system design and analysis.

In contrast, other tools listed have different primary purposes. The Unified Modeling Language (UML) includes various diagrams to model software systems broadly, not exclusively focused on data movement. Entity-Relationship Diagrams (ERDs) are used to illustrate the relationships between data entities rather than the flow of information. Flowcharts depict sequences of operations or steps but are not primarily used to show data flow like a DFD. These differences highlight why the Data Flow Diagram is the most appropriate choice for this question.