Question: What triggers the increment of the 'Attempted InsertSubscriberData requests received from a HLR during GPRS Update Location procedure' performance measurement in a Core Network (CN) Packet Switched (PS) domain?
Option 1: Successful completion of a GPRS Update Location procedure
Option 2: Receipt of a 'MAP-INSERT-SUBSCRIBER-DATA' service request during a GPRS Update Location procedure
Option 3: Transmission of a 'MAP_UPDATE_LOCATION' service request to the HLR
Option 4: Failure of an InsertSubscriberData request sent to the SGSN
Explanation: This measurement counts InsertSubscriberData requests received from the Home Location Register (HLR) during the GPRS Update Location procedure. The correct trigger is the receipt of a 'MAP-INSERT-SUBSCRIBER-DATA' service request, relating to subscriber data updates during location updates in the packet-switched domain of the core network.