Question: In a UMTS network, when is the `SMS.SuccMsPresentPS` counter incremented in relation to the SGSN?
Option 1: When an MS (Mobile Station) sends a request to receive SMS and the SGSN approves it without HLR interaction.
Option 2: Upon receipt of a notification from the MS that it has successfully received an SMS via the GSM network.
Option 3: When the SGSN receives a return result from the HLR in response to a MAP_READY_FOR_SM message with reason 'MS present'.
Option 4: After a successful SMS transmission over the UMTS network, acknowledged by the MS.
Explanation: The `SMS.SuccMsPresentPS` counter increments based on SGSN and HLR interaction, specifically when the SGSN receives a response to a MAP_READY_FOR_SM message with 'MS present' as the reason, indicating the MS is ready to receive Short Messages, confirmed through network signaling involving both SGSN and HLR.