Question: What is a prerequisite for the presence of the EFFDN (Fixed Dialling Numbers) file in a USIM, in terms of service availability?
Option 1: Service n° 1 and/or service n° 90 being "available"
Option 2: The presence of EFADN (Abbreviated Dialling Numbers) in the USIM
Option 3: Service n° 2 and/or service n° 89 being "available"
Option 4: The default enablement of FDN restrictions on all bearers
Explanation: According to the specifications, for the EFFDN file to be present in the USIM, either service n° 2 or service n° 89 (or both) must be indicated as "available". This condition highlights the dependency of EFFDN's presence on the availability of these specific services, which are likely related to fixed dialling number functionalities.