Question: In a USIM application, if service n°79 is "available", what is the implication for the EFPNNI (PLMN Network Name Icon) file?
Option 1: The EFPNNI file shall contain only one link to the PLMN network name icon.
Option 2: The presence of the EFPNNI file is mandatory, containing at least one link to the PLMN network name icon.
Option 3: The EFPNNI file is optional and its presence is determined by the Mobile Equipment (ME).
Option 4: The EFPNNI file shall be absent to indicate service n°79's availability.
Explanation: According to the specification, if service n°79 is "available", the EFPNNI file **shall be present**, indicating a mandatory presence. This file can contain one or several links to the PLMN network name icon, allowing flexibility in its structure but ensuring at least one link is included to signify the service's availability.