What does maintenance in a software system typically refer to?

Maintenance in a software system typically encompasses a range of activities aimed at ensuring the software continues to function properly and meet user needs over time. This includes changes that arise from error corrections, which involve fixing bugs or issues that have been identified after the system's initial deployment. Additionally, maintenance involves performance improvements, ensuring that the software operates efficiently and effectively as conditions change or as user demands evolve. Enhancements might also be implemented during maintenance to add new features or improve existing ones based on user feedback or changing requirements.

This comprehensive view aligns with the best practices in software development, where ongoing maintenance is crucial for sustaining usability, security, and overall performance. While aspects like user interface enhancements and security patches could fall under maintenance, they are not the entire scope; thus, option C captures the full range of maintenance activities more accurately than other choices.