Question: What assumption does a Mobile Station (MS) make about the Registered PLMN's (RPLMN) access technology if the EFRPLMNAcT (RPLMN Last used Access Technology) Elementary File (EF) is absent on the Subscriber Identity Module (SIM)?
Option 1: The MS assumes the RPLMN uses the latest available access technology (e.g., 5G).
Option 2: The MS assumes the RPLMN uses a default access technology based on the MS's current location.
Option 3: The MS assumes the RPLMN supports all access technologies (e.g., GSM, UMTS, LTE, 5G) simultaneously.
Option 4: The MS assumes the RPLMN access technology is GSM.
Explanation: This is because, in the absence of explicit information, the Mobile Station (MS) defaults to assuming the Registered PLMN's (RPLMN) access technology is GSM, highlighting a default fallback behavior.