What is causing this issue?

In setting up the wireless network, it is desired that the DHCP server that is configured in WLC1 provides IP addressing to the WLAN. When devices attempt to join the network, they fail to receive an IP address in the range provided by the DHCP server in WLC1, but they do receive an IP address from the DHCP server in SW1.

What is causing this issue?
A . The external DHCP server in SW1 will always be the preferred DHCP server and WLC1 will always be the secondary DHCP server in the WLA
C . The DHCP server address for SW1 needs to be removed from the DHCP server configuration in WLC1.
D . The primary DHCP server address in WLC1 is incorrect.
E . The primary DHCP server configured in WLC1 is not enabled.

Answer: D