Question: In a Short Message Service (SMS) scenario, where the originating Short Message Entity (SME) is a mobile station, how does the originating SME request a reply path?
Option 1: By setting the TP-Reply-Path parameter in the SMS SUBMIT PDU of the original Short Message (SM)
Option 2: By sending a separate SMS control message to the Serving Cell (SC) requesting a reply path
Option 3: Through implicit request, where the SC automatically sets up a reply path for all submitted SMS
Option 4: By modifying the SMS DELIVER PDU of the original Short Message (SM) before sending it to the destination
Explanation: This is correct because, according to the specified telecom protocol for SMS, when an originating SME wants a reply path, it explicitly sets the TP-Reply-Path parameter within the SMS SUBMIT PDU of the original Short Message, informing the Serving Cell to facilitate a reply path if supported.