A is in top-down format and shows each level of design, its relationship to other levels, and its place in the overall system hierarchy.

Structured Systems Analysis & Design Method

Explanation:

Structured Systems Analysis & Design methodologies have been used to document, analyze, and design information systems since the 1970s. Structured refers to the fact that the techniques are step by step, with each step building on the previous one. Structured methodologies are top-down, progressing from the highest, most abstract level to the lowest level of detail—from the general to the specific. Structured development methods are process-oriented, focusing primarily on modeling the processes, or actions that capture, store, manipulate, and distribute data as the data flow through a system. The late mainframe period gave rise to structured methods as some of the earliest principles of software engineering to help overcome the software crisis. Structured methods are approaches for functionally decomposing software designs, e.g., expressing software designs in high-level components, which are further refined in terms of lower level components.

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