Which of the following measures increases availability in computing systems?

The measure that increases availability in computing systems is redundant servers. Redundant servers are part of a reliability and availability strategy to ensure that a system remains operational even if one or more components fail. By having multiple servers that can handle the workload, the system can continue to function without disruption. This means that even in the event of a server failure, users can still access services without noticeable downtime, thus enhancing the overall availability of the computing environment.

In contrast, strong encryption primarily focuses on data confidentiality and security rather than availability. Access controls are critical for security by managing who can access resources, but they do not inherently affect the system's availability. Data sanitization is important for protecting sensitive information but does not contribute to making systems more resilient to downtime or failures.