Final answer:
The option 'Buy a commercial working software' does not belong to the dimensions of requirements reuse; it refers to software procurement rather than reusing requirements as part of the software development process.
Step-by-step explanation:
The question is about identifying which option does NOT belong to the dimensions of requirements reuse in the context of software engineering. Requirements reuse is a process in software development where existing requirement assets, such as specifications, designs, test cases, or code, are used in new projects to reduce costs and development time. Looking at the options provided:
- Reuse mechanism refers to the method or process by which the reuse of requirements is implemented, thus it belongs to the dimensions of requirements reuse.
- Buy a commercial working software is not typically considered a dimension of requirements reuse because it refers to acquiring ready-to-use software rather than reusing specific requirements. This is related more to software procurement than to requirements reuse.
- Extent of modification refers to the degree to which reused requirements need to be altered to fit into the new project context, making it a dimension of requirements reuse.
- Extent of reuse indicates how much of the previously developed requirements can be reused in a new project, which is also a dimension of requirements reuse.
Therefore, the option that does NOT belong is Buy a commercial working software, as it is not a dimension of requirements reuse but rather a separate approach to acquiring software solutions.