Question: What type of error is indicated by the DIAMETER_ERROR_OUT_OF_RESOURCES (4121) Experimental-Result-Code value in the context of MBMS Session Start procedure?
Option 1: Permanent failure due to invalid request
Option 2: Transient failure due to temporary resource shortage
Option 3: Authentication failure due to incorrect credentials
Option 4: Authorization failure due to insufficient privileges
Explanation: The DIAMETER_ERROR_OUT_OF_RESOURCES (4121) Experimental-Result-Code value is specifically defined for transient failures, indicating that the MBMS Session Start procedure could not be performed due to a temporary resource shortage in the GGSN. This allows the BM-SC to re-try later when resources become available.