Which security goal is defined by guarding against improper information modification or destruction?

The correct answer is integrity because it specifically pertains to the assurance that information is protected from unauthorized modification or destruction. Integrity ensures that data remains accurate, consistent, and trustworthy over its entire lifecycle. This security goal is crucial in safeguarding data, as any unauthorized alterations can lead to misinformation and compromise the reliability of the system.

For instance, in the context of databases, maintaining integrity means that data should not be changed by unauthorized users or processes. Mechanisms like checksums, hash functions, and digital signatures are often employed to maintain data integrity. By implementing these measures, organizations can secure their information against both accidental and malicious changes, thereby preserving its authenticity and accuracy.

The other options, while relevant to the broader context of information security, do not directly address the specific concept of protecting against improper modifications. Quality pertains to the overall standard of the output, reliability relates to how consistently a system performs as expected, and availability focuses on ensuring that data and systems are accessible when needed.