Network Administrator Patricia is doing an audit of the network. Below are some of her findings concerning DNS. Which of these would be a cause for alarm? Select the best answer.

A.
There are two external DNS Servers for Internet domains. Both are AD integrated.

B.
All external DNS is done by an ISP.

C.
Internal AD Integrated DNS servers are using private DNS names that are unregistered.

D.
Private IP addresses are used on the internal network and are registered with the internal AD integrated DNS server.