Several Mobile Users Are Reporting Issues Connecting to the WLAN

Several mobile users are reporting issues connecting to the WLAN within a warehouse. A technician tests wireless connectivity in the lobby and is able to connect successfully. Mobile users can connect to the Internet using cellular service, but they cannot access any internal resources on the WLAN. The technician received alerts of devices failing throughout the network due to a power outage. Which of the following is MOST likely causing the wireless issues?

A) SSID is configured to not broadcast.
B) The system locked out for all wireless users.
C) The DHCP scope for WLAN is full.
D) The WAP in the warehouse is down.