Assuming that systems are synchronized, which action could take place if the fail over cable is connected correctly and working properly, but the systems cannot communicate over the network due to…

Network failover relies on IP network communication; if external network problems prevent communication, network failover cannot occur, and the standby system would not assume active mode if the failover cable is functional.

In high-availability configurations, a dedicated failover cable (often a serial or dedicated Ethernet link) provides a direct, out-of-band communication path between HA peers for heartbeat and state synchronization. If this dedicated link is functional, the standby system will continue to receive heartbeat signals from the active device and maintain its standby role, regardless of external network issues or the state of network failover.

This is incorrect because the functioning failover cable ensures the standby system is aware of the active system's status, preventing an unprompted failover.

The standby system would not go into active mode if the failover cable is correctly conveying heartbeat information, irrespective of external network conditions.