Question: What is the responsibility of the CGF regarding persistent CDR storage and transfer to the BD via the Bx reference point?
Option 1: The CGF is responsible for real-time processing of CDRs, but not for storing or transferring them.
Option 2: The CGF is responsible for preparing CDR files, storing them persistently, and transferring them to the BD via the Bx reference point.
Option 3: The CGF only provides routing information for CDRs, but does not store or transfer them.
Option 4: The CGF is responsible for compressing CDR files before transferring them to the BD.
Explanation: According to the text, the CGF is indeed responsible for persistent CDR storage, preparing CDR files, and transferring them to the BD via the Bx reference point. This includes providing one or more files for storing CDRs after potential reformatting to comply with the Bx file format specified in TS 32.297.