Question: What is the primary purpose of the `AccessStratumRelease` Information Element (IE) in the Radio Resource Control (RRC) protocol?
Option 1: To indicate the UE's (User Equipment) preferred radio access technology (RAT) for connection.
Option 2: To negotiate the maximum bandwidth allocation for a UE during an active session.
Option 3: To signal the UE's support for specific frequency bands to the base station.
Option 4: To inform the network about the highest 3GPP release (e.g., Rel-15, Rel-16) supported by the UE.
Explanation: The `AccessStratumRelease` IE communicates the highest 3GPP release version (such as Rel-15, Rel-16, etc.) supported by the User Equipment (UE), ensuring the network knows which features and protocols can be used for compatible and optimal service delivery.