Which phase of a waterfall approach involves creating a sequence diagram for program components?

The correct answer is the design phase because this is when detailed planning for the system's architecture and components occurs. In this phase, diagrams such as sequence diagrams are created to illustrate how different components of the program will interact with one another. A sequence diagram specifically helps identify the order of operations and the flow of messages between components, providing a visual representation of the system's functionality and behavior as it processes requests.

During the design phase, the focus shifts from understanding what the system needs to do—an aspect addressed during requirements gathering—to how the system will fulfill those requirements. This includes defining the structure, interfaces, and interactions between various components.

In contrast, the requirements gathering phase is primarily concerned with identifying and documenting what the stakeholders need from the system, rather than detailing the how. The testing phase involves verifying that the system meets the specified requirements and works as intended, so it does not involve creating design documentation. Finally, the maintenance phase occurs after the system has been developed and deployed, focusing on bug fixes and updates rather than on designing or planning new components.