Question: In an LTE network, when an MME sends a Subscriber Location Report to a GMLC during an emergency call, which of the following information is OPTIONALLY included in the message, if available?
Option 1: IMEI, IMSI, MSISDN, and Serving Cell Identity
Option 2: Only IMEI and IMSI
Option 3: Serving Cell Identity and Location Estimate Age
Option 4: MME Address and Charging Information
Explanation: According to location services procedure in an LTE network, when the MME sends a Subscriber Location Report to the GMLC, it must include certain mandatory fields. Serving Cell Identity may also be sent if available, making it optional. The Location Estimate Age is part of the location information that was obtained, implying its inclusion when a location estimate is provided, thus both are conditionally included based on availability and context.