Question: When disabling usage monitoring for a PCC/ADC rule in a telecom network, which of the following methods involves modifying an existing rule rather than replacing it with a new one?
Option 1: The PCRF generates a new PCC/ADC rule without a monitoring key and replaces the existing rule.
Option 2: The operator selects a specific monitoring key value for disabled rules, and the PCRF updates this key in the existing PCC/ADC rule.
Option 3: The PCEF/TDF directly stops collecting usage information upon receiving a disable command from the PCRF without any rule modifications.
Option 4: The PCRF removes all associated monitoring keys from the existing PCC/ADC rule without providing a new rule or modifying the existing one.
Explanation: This approach describes a method where the existing PCC/ADC rule is modified by updating its monitoring key to a specific value indicating that usage monitoring is disabled, rather than generating a new rule or stopping collection without modification.