question: What is the key characteristic of a roaming broker enabled Home Environment? [3GPP Release 18] option 1: It has a direct commercial agreement with different serving networks. option 2: It interworks with one or more serving network operators. option 3: It uses fraud and cost control mechanisms to ensure charges do not exceed credit limits. option 4: It routes registration requests to its serving networks. option 5: It is capable of operating as a roaming broker. 