Question: At what point is a mobile originating call considered successful for counting in the 'Successful mobile originating call' measurement in a UMTS/GSM Core Network (CN) Circuit Switched (CS) domain?
Option 1: Upon transmission by the MSC-S of an 'Alerting' message to the originating mobile.
Option 2: When the mobile user initiates a call setup request to the MSC-S.
Option 3: After the call is successfully connected and the user starts communicating.
Option 4: When the MSC-S receives a call release from the terminating party.
Explanation: A mobile originating call is considered successful for this measurement upon the transmission by the MSC-S of an 'Alerting' message to the originating mobile, indicating the call setup has progressed to alerting the called party, marking a successful initiation from the originating side's perspective.