An administrator needs to add fault tolerance capabilities to a server. Which of the following is the BEST solution to accomplish this?

Moving from 32-bit to 64-bit architecture improves performance and memory addressing but does not directly add fault tolerance against hardware failures.

A PBX (Private Branch Exchange) card is used for telephony systems to manage internal and external calls and does not contribute to server fault tolerance.

Installing a second NIC card enables network fault tolerance through technologies like NIC teaming (also known as bonding or LACP). If one network interface fails, the other can seamlessly take over, ensuring continuous network connectivity for the server and preventing service disruption for critical applications.

A 'fail-over cable' is not a standard or recognized component for adding fault tolerance; fault tolerance is achieved through redundant hardware and software configuration, not a specific cable.