Which of the following logs would contain general messages about system activity?

The log that would contain general messages about system activity is the syslog or messages log. This log serves as a centralized repository for various types of system messages, including notifications from the kernel, system services, and application programs. It is designed to provide insights into system operations, which can help administrators diagnose issues, monitor performance, and understand general system behavior.

The kernel ring buffer primarily records low-level kernel messages and is mainly used for debugging related to the kernel's operation, rather than general system activity.

GDM logs are specific to the GNOME Display Manager and primarily contain information related to user login sessions and graphical environment activities. Therefore, they do not encompass the broader scope of general system activity.

CUPS logs are related to the Common UNIX Printing System and focus on print jobs and printer status, which is a more specialized area and does not cover overall system messages.

Thus, the syslog or messages log effectively aggregates diverse system messages, making it the correct choice for monitoring general system activity.