Question: In a Fixed xDSL origination scenario within the home service area, what action may be taken by the S-CSCF when forwarding the SIP INVITE request, subject to operator policy, if network-provided location information is not already present?
Option 1: Insert a temporary identifier for billing purposes
Option 2: Insert a reference location of the user (e.g., line identification) determined by the operator as part of the user profile
Option 3: Request additional authentication from the UE before proceeding
Option 4: Modify the initial SDP to limit media stream capabilities
Explanation: This is correct because, in Fixed xDSL origination within the home service area, when the S-CSCF forwards the request, it may insert a reference location of the user if network-provided location information is not already present. This action is subject to operator policy and the reference location is determined by the operator as part of the user profile.