Refer to the exhibit.

What might be the reason of these failed attempts in ACS?

A.
The wrong shared secret is configured on the AAA client or ACS.

B.
The request is coming from a AAA client that is configured only for RADIUS on ACS.

C.
The request is coming from a AAA client that is configured only for TACACS+ on ACS.

D.
The PC that is trying to access the device is outside the known subnet.