Question: Under what circumstances can an MME release a UE in ECM-CONNECTED mode with an active emergency bearer service for load re-balancing?
Option 1: When the UE initiates a Service Request.
Option 2: When the MME needs to perform a software upgrade.
Option 3: In critical conditions such as the need to perform an MME node restart.
Option 4: When the UE's emergency bearer service is deactivated.
Explanation: According to load re-balancing procedures, an MME should not release a UE in ECM-CONNECTED mode with an active emergency bearer service for load re-balancing. However, in critical conditions such as the need to perform an MME node restart, the MME may release the UE. This ensures that the MME can maintain its functionality and provide emergency services when needed.