Which directory is commonly used in Linux systems to store log files, including syslog and Apache access logs?

The correct answer is the directory "/var/log," which is the standard location for log files in Linux systems. This directory is designated for variable data files, which are files that can change in size or content, such as logs produced by system processes and applications.

Logs are critical for system monitoring and debugging, as they record various events and activities that occur on the system. Within "/var/log," you will commonly find subdirectories and files related to different services and applications, including syslog, which captures system messages, and Apache access logs, which record requests made to the Apache web server.

The other options do not reflect standard practices in Linux file system hierarchy: "/etc/log" is not a recognized directory for logs; "/root/log" suggests a log directory within the root user's home directory, which is not a standard convention; and "/lib/log" does not align with the general purpose of the "/lib" directory, which primarily contains essential shared libraries and kernel modules, not log files. Therefore, "/var/log" is the appropriate and commonly used directory for storing logs on Linux systems.