Question: After an Answer To Reset (ATR) in a SIM-ME interface, how is the initial file selected for further operations?
Option 1: The Current Directory is explicitly set to the first available Elementary File (EF) by default.
Option 2: The Master File (MF) is implicitly selected and becomes the Current Directory.
Option 3: The User Equipment (UE) selects a file based on the last used application.
Option 4: A random Elementary File (EF) within the SIM is chosen for initial operations.
Explanation: According to standard practices in SIM-ME interfaces, after an Answer To Reset (ATR), the structure of the card's file system is initialized with the Master File (MF) as the root. This MF then becomes the Current Directory from which further file selections can be made using the SELECT function, ensuring a standardized starting point for all subsequent operations.