Question: In a NIDD-Authorization-Request sent from the SCEF to the HSS, what is the primary purpose of the optional 'Service-Selection' AVP?
Option 1: To specify the requested validity time for the authorization
Option 2: To identify the MSISDN associated with the NIDD request
Option 3: To indicate the specific service(s) for which NIDD authorization is being requested
Option 4: To provide an external identifier for the user equipment (UE)
Explanation: The 'Service-Selection' AVP in a NIDD-Authorization-Request is used to specify the particular service(s) that the requesting entity is seeking authorization for, allowing the HSS to evaluate and respond with an authorization decision tailored to those services.