What is the purpose of access code 9 based on the following information?

A.
The access code 9 connects a caller to the operator when they press 9 on their phone keypad.

B.
This is a level 1 security

C.
The access code 9 is the access code that internal users must use to make PSTN calls.

D.
he access code 9 is required when interfacing with a traditional PBX system