Question: What is the primary purpose of the optional alpha-identifier included by the SIM in the response data to the ENVELOPE (MO SHORT MESSAGE CONTROL) message?
Option 1: To authenticate the user for secure transactions
Option 2: To inform the user at the time the response is received by the Mobile Equipment (ME)
Option 3: To initiate a call setup process without user intervention
Option 4: To update the SIM's software with new security patches
Explanation: The correct answer highlights the main objective of including an alpha-identifier in the response data, which is to notify the user immediately when the ME receives the response, enhancing user experience by providing timely feedback.