Question: In a scenario where a functional split of PGW into PGW-C and PGW-U is supported, which of the following functionalities are preserved in accordance with the specified standards?
Option 1: Only offline charging as defined by charging management standards
Option 2: Online charging, offline charging, and usage monitoring control as defined by relevant charging and architecture standards
Option 3: Policy and Charging Control Architecture alone as per policy and charging control standards
Option 4: Neither online nor offline charging functionalities are preserved
Explanation: When a functional split of PGW into PGW-C (Control Plane) and PGW-U (User Plane) is supported, the architecture must preserve both online and offline charging functionalities, as well as usage monitoring control. This ensures seamless integration of charging and usage monitoring across the split architecture, maintaining the integrity of these critical functions in telecom networks.