Network Administrator Patricia is doing an audit of the network.

Explanations:

A. There are two external DNS Servers for Internet domains. Both are AD integrated. This is the correct answer. Having an AD integrated DNS external server is a serious cause for alarm. There is no need for this and it causes vulnerability on the network.

B. All external DNS is done by an ISP.

This is not the correct answer. This would not be a cause for alarm. This would actually reduce the company's network risk as it is offloaded onto the ISP.

C. Internal AD Integrated DNS servers are using private DNS names that are unregistered. This is not the correct answer. This would not be a cause for alarm. This would actually reduce the company's network risk.

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

This is not the correct answer. This would not be a cause for alarm. This would actually reduce the company's network risk.