What would be the possible cause of this failure?

Refer to the exhibit.

One of the Windows machines in your network is having connectivity issue by using 802.1X. Windows machines are setup to acquire an IP address from DHCP server configured on the switch, which is supposed to hand out IP address from 50.1.1.0/24 network, and forward AAA requests to the Radius server at 161.1.7.14 using shared key "cisco".

Knowing that interface Gi0/2 on the switch may receive authentication requests from other devices and looking at the provided switch configuration.

What would be the possible cause of this failure?
A . authentication port-control has not been set on g0/2
B . an incorrect radius server address is defined
C . an incorrect pre-authentication acl has been configured
D . aaa dot1x authentication has not been configured
E . an incorrect dhcp pool has been not configured
F . aaa login authentication is not configured
G . authentication is not enabled on g0/2

Answer: B