Question: In a UICC with a present GSM application, where is the first EFADN (Abbreviated Dialling Numbers) of the DFPHONEBOOK mapped to ensure backwards compatibility, and which entity should not access this file?
Option 1: Mapped to DFGSM, inaccessible to GSM ME
Option 2: Mapped to DFTELECOM, inaccessible to 3GPP ME
Option 3: Mapped to DFISMS, inaccessible to LTE UE
Option 4: Mapped to DFLTE, inaccessible to GSM ME
Explanation: To ensure backwards compatibility in a UICC with an existing GSM application, the first EFADN of the DFPHONEBOOK is specifically mapped to the DFTELECOM file. This arrangement allows for continuity with older systems. Additionally, to maintain separation and prevent potential conflicts or unauthorized access, a 3GPP Mobile Equipment (ME) is restricted from accessing this particular file directly.