Question: What type of setup message is sent by the mobile station's call control entity when initiating an emergency call?
Option 1: SETUP message
Option 2: EMERGENCY SETUP message
Option 3: CALL INITIATED message
Option 4: MM CONNECTION REQUEST message
Explanation: According to the specification, when the mobile station is initiating an emergency call, it sends an EMERGENCY SETUP message to its peer entity. This is a specific type of setup message that contains information such as the emergency category, if available at the MS.