Question: In the process of sending an originated short message, what is the primary purpose of an SMS-IWMSC potentially interrogating the HLR in the context of inter-network messaging?
Option 1: To verify the sender's location for billing purposes.
Option 2: To check if an SMS Interworking agreement exists between the originating and recipient's networks.
Option 3: To retrieve the recipient’s phone number for message routing.
Option 4: To update the sender’s SMS service settings.
Explanation: The primary reason for an SMS-IWMSC to interrogate the HLR (Home Location Register) is to verify if there is a valid SMS Interworking agreement between the two networks involved in the message exchange. This ensures that the networks have a mutually agreed-upon arrangement for handling SMS traffic between them, which is crucial for successful inter-network messaging.