Which of the following best describes "availability" in the context of information security?

"Availability" in the context of information security refers to the assurance that systems, services, and information are accessible and usable as needed by authorized users. This concept is one of the key principles in the CIA triad of information security, which includes confidentiality, integrity, and availability. Ensuring availability means implementing measures to protect against downtime, service interruptions, and denial-of-service attacks, which could prevent users from accessing critical systems and data when required.

The correct choice encapsulates this understanding by emphasizing the importance of having systems and information readily available at all times, thus supporting operational continuity and reliability in information security practices.