Question: What is the primary purpose of including the Progress Indicator information element in a message sent by the network?
Option 1: To request the Mobile Station (MS) to release the current call.
Option 2: To inform the MS about an incoming call from another network.
Option 3: To pass information about the call in progress, especially during interworking and/or to attach the user connection for speech.
Option 4: To instruct the MS to perform a handover to a different cell.
Explanation: The Progress Indicator is used by the network to provide information about the ongoing call, particularly when interacting with other networks or when setting up the user's speech connection. This ensures that the Mobile Station (MS) and the network are synchronized regarding the call's status and can take appropriate actions as needed.