Which maintenance type involves restructuring and optimizing code?

The maintenance type that focuses on restructuring and optimizing code is perfective maintenance. This type of maintenance is aimed at enhancing the features and performance of a software system after its initial deployment. It involves making improvements to existing functionality, optimizing the code, and refining the system to better meet user needs or adapt to changing requirements.

Perfective maintenance is crucial for extending the life of a software application and ensuring that it continues to perform efficiently as technology and user expectations evolve. By optimizing code, developers can enhance system performance, increase reliability, and often improve user satisfaction.

In contrast, preventive maintenance aims to prevent potential issues before they arise, corrective maintenance addresses bugs or errors that have been found, and adaptive maintenance modifies the software to accommodate changes in the environment or platform. Each of these types serves a specific purpose, but when it comes to restructuring and optimizing code specifically for enhancement, perfective maintenance is the correct focus.