Question: What is the primary purpose of the CounterExpiryDate AVP in the Online Charging System (OCS), as related to the identified counter by the CounterID AVP?
Option 1: To reset the counter value to zero at the start of each billing cycle.
Option 2: To trigger a notification to the subscriber when the counter reaches its limit.
Option 3: To specify the timestamp when the current counter value expires and may be updated or reset.
Option 4: To synchronize the counter with the system clock for accuracy.
Explanation: The CounterExpiryDate AVP is crucial for managing counters in the OCS, particularly in determining when a counter's current value is set to expire. This timestamp directly influences how and when the associated counter (identified by the CounterID AVP) is updated or reset, ensuring accurate charging management based on time-sensitive counter values.