Question: In the context of Short Message Service (SMS), what is the primary role of a Short Message Service Centre (SC) in the transfer of short messages?
Option 1: To manage higher layer applications for User Equipment (UE)
Option 2: To handle billing and charging for SMS services
Option 3: To serve as an interworking and relaying function between Mobile Stations (MS) and Short Message Entities (SME)
Option 4: To encrypt messages for secure transmission over the air interface
Explanation: The SC's primary role is facilitating communication between the mobile network (via the Mobile Station/MS) and external entities (Short Message Entities/SME), enabling seamless short message transfer, crucial for SMS services' operational integrity across different domains.