Explanation
NIC stands for network interface card, which is a hardware component that allows a server to connect to a network. Configuring NICs in pairs on a server would provide network redundancy, meaning that if one NIC fails, the other one can take over and maintain network connectivity. The other options are not related to network redundancy.

Explanation
The audit.log file is a file that records security-related events on a Linux server, such as user login, file access, and system commands. The logrotate utility is a tool that rotates, compresses, and deletes old log files based on certain criteria, such as size, time, or frequency. To decrease the number of times the log rotates without losing any information, the administrator should increase the audit.log file size in the appropriate configuration file, such as /etc/logrotate.conf or /etc/logrotate.d/auditd. Verified References: [audit.log], [logrotate]

SIEM is the tool that will analyze network logs in real time to report on suspicious log events. SIEM stands for Security Information and Event Management, which is a software solution that collects, analyzes, and correlates log data from various sources, such as servers, firewalls, routers, antivirus software, etc. SIEM can detect anomalies, patterns, trends, and threats in the log data and generate alerts or reports for security monitoring and incident response. SIEM can also provide historical analysis and compliance reporting for audit purposes.
Reference:
https://www.manageengine.com/products/eventlog/syslog-server.html