To assign an IP address to the GigabitEthernet1 interface, the engineer needs to ensure that the interface is configured to support IPv4 addressing and then assign the specific IP address. Option B, "Router(config-vrf)#address-family ipv4", is required to specify that IPv4 addressing is being configured within the VRF. Option E, "Router(config-if)#ip address 192.168.1.1 255.255.255.0", assigns the specific IP address and subnet mask to the GigabitEthernet1 interface. References := The explanation can be corroborated with information available in Cisco's official documentation and training materials for Implementing and Operating Cisco Service Provider Network Core Technologies.