Question: What happens to a file on a Subscriber Identity Module (SIM) after an INVALIDATE function is successfully executed, in terms of its availability for various operations?
Option 1: The file becomes available for all functions except READ and WRITE.
Option 2: The file remains unchanged and accessible for all functions as before.
Option 3: The file is permanently deleted from the SIM.
Option 4: The file is no longer available for any function except SELECT and REHABILITATE.
Explanation: According to telecom standards for Subscriber Identity Module (SIM) management, when a file is invalidated, it is logically set aside and not accessible for most operations to maintain data integrity and security. However, to allow for recovery or specific access, the standard permits two exceptions: SELECT (to identify or query the file's existence/status) and REHABILITATE (to restore the file's validity). This ensures a balance between security and operational flexibility within the SIM's application environment.