Question: In a Dialled Service CAMEL Subscription Information (D-CSI) context, what is the primary purpose of the 'DP Criterion' within each entry of the DP Criteria list?
Option 1: To specify the gsmSCF address for service logic execution
Option 2: To identify the service key for CAMEL phase determination
Option 3: To define the default call handling in case of errors
Option 4: To indicate when the gsmSSF should request instructions from the gsmSCF, based on a destination number
Explanation: The 'DP Criterion' indicates when the gsmSSF shall request instructions from the gsmSCF, defined as a destination number, aligning with how CAMEL services are triggered for customized mobile network service handling.