A user cannot reach the internet from a workstation. A systems administrator performs diagnostics with the following results: Which of the following is the cause for lack of internet connectivity?

If the workstation is not using a DNS server, it would be unable to resolve domain names, but it could still access internet resources directly by IP address if network connectivity is otherwise sound.

While an unreachable network gateway certainly causes a lack of internet connectivity, an incorrect network mask on the workstation could be the underlying reason for the gateway being unreachable from the workstation by miscalculating the local subnet.

An incorrect network mask prevents the workstation from correctly identifying whether destination IP addresses are on the local network or require routing through the default gateway, thereby disrupting all external network communication, including internet access.

A company's firewall blocking connections would prevent internet access, but this typically occurs at a network perimeter device and not due to a misconfiguration on the workstation's local network interface itself like an incorrect network mask.