John, a malicious hacker, forces a router to stop forwarding packets by flooding it with many open connections simultaneously so that all hosts behind it are effectively disabled. Which of the…

ARP spoofing involves sending forged ARP replies to associate the attacker's MAC address with a legitimate IP, enabling traffic interception - it does not flood connections to exhaust router resources.

A replay attack involves capturing valid authentication or data packets and retransmitting them later to gain unauthorized access, not flooding a device with connections.

A rainbow attack uses precomputed hash tables to crack password hashes offline and has nothing to do with network flooding or router resource exhaustion.

A DoS attack works by overwhelming a target system - in this case a router - with excessive requests or open connections until it can no longer process legitimate traffic. Flooding with open connections exhausts the router's connection-state table or processing capacity, effectively taking it offline. This matches the classic definition of DoS: denying service to legitimate users by resource exhaustion.