Question: In which GMM-REGISTERED substate does the MS perform a combined GPRS detach procedure for non-GPRS services only, and user data and signalling information may be sent and received?
Option 1: GMM-REGISTERED.NORMAL-SERVICE
Option 2: GMM-REGISTERED.SUSPENDED
Option 3: GMM-REGISTERED.IMSI-DETACH-INITIATED
Option 4: GMM-REGISTERED.PLMN-SEARCH
Explanation: The correct answer is GMM-REGISTERED.IMSI-DETACH-INITIATED, as this substate is entered when the MS performs a combined GPRS detach procedure for non-GPRS services only (detach type "IMSI Detach"), and user data and signalling information may be sent and received.