Which of the following is not considered a phase of the Software Development Life Cycle?

In the context of the Software Development Life Cycle (SDLC), various phases are integral to the process of software development. The phases typically include requirements gathering, design, implementation, testing, deployment, and maintenance.

Focusing on the given options, "Development" is often considered synonymous with "Implementation" in SDLC nomenclature. When software is developed, it is implemented according to the design specifications, which means that development itself is part of the implementation phase. This understanding distinguishes "Development" as not a separate phase but rather as an activity that occurs within the implementation phase of the SDLC.

By recognizing how the phases interrelate, it becomes clear why "Development" is not categorized as a distinct phase within the lifecycle while Testing, Implementation, and Design are clearly defined and recognized as separate phases.