Question: Which of the following statements accurately describes the support for Supplementary Services for SMS over General Packet Radio Service (GPRS)?
Option 1: All Supplementary Services are fully supported for SMS over GPRS, including user control via the Supplementary Service protocol.
Option 2: Only the invocation of Call Forwarding Supplementary Service is supported for SMS over GPRS, with no user control available.
Option 3: Only the invocation of Call Barring Supplementary Service is supported for SMS over GPRS, with no user control available via the Supplementary Service protocol.
Option 4: All Supplementary Services are available but only through interworked packet data networks, not directly on GPRS.
Explanation: This option correctly reflects that for SMS over GPRS, the specification only supports the invocation of Call Barring Supplementary Service. Additionally, it accurately notes that user control through the Supplementary Service protocol is not supported over GPRS, aligning with the nuances of how supplementary services are defined and limited for GPRS in telecom networks.