Question: What triggers the increment of the `MM.SuccUpdateGprsLocationHlr` measurement in a telecommunications network?
Option 1: Receipt of a 'MAP_UPDATE_LOCATION ack' service response/confirm indicating a successful GPRS Update location
Option 2: Sending a 'MAP_CANCEL_LOCATION' service request to an HLR-operator for a Detach procedure
Option 3: Failure of a GPRS Attach procedure due to invalid user credentials
Option 4: Completion of a voice call in a UMTS network
Explanation: The `MM.SuccUpdateGprsLocationHlr` measurement counts the number of successful GPRS Update Locations returned from the Home Location Register (HLR). It is incremented upon receipt of a 'MAP_UPDATE_LOCATION ack' service response/confirm, signifying a successful update, related to managing packet switching operations at the SGSN function level.