A cloud administrator runs a maintenance script to remove unused resources. After the maintenance has been performed, users report they can no longer access the application website. The administrator

Removing inactive accounts would affect user authentication but would not prevent all users from accessing the application website if the server is otherwise operational and reachable.

If outdated firewall rules were removed, and these rules were essential for inbound access, the server would not be 'responding on the proper ports' from a client perspective, contradicting the problem description.

Removing stale DNS entries would cause users to be unable to resolve the application's domain name to its corresponding IP address, even if the server is running and responding on its ports. This results in users being unable to access the website by its name, perfectly matching the described symptoms.

Removing orphaned resources is a general term; while a DNS entry could be considered an orphaned resource if the target no longer exists, 'removing stale DNS entries' (C) is a more specific action that directly explains the inability to access a website by name while the server is running.