A company has deployed a U1981 and is connected to the PSTN through a PRA trunk. If you want external users to be unable to call external users after incoming calls through this trunk, it is recommended to configure which of the following trunk outgoing call permissions is recommended?

A company has deployed a U1981 and is connected to the PSTN through a PRA trunk. If you want external users to be unable to call external users after incoming calls through this trunk, it is recommended to configure which of the following trunk outgoing call permissions is recommended?
A . Intra-office call
B . Local call
C . Domestic long distance calls
D . International long distance calls

Answer: A