How does an administrator configure an Expressway to make sure an external caller cannot reach a specific internal address?

How does an administrator configure an Expressway to make sure an external caller cannot reach a specific internal address?
A . add the specific URI in the firewall section of the Expressway and block it
B . block the call with a call policy rule in the Expressway-E
C . add a search rule route all calls to the Cisco UCM
D . configure FAC for the destination alias on the Expressway

Answer: B