An elastic network interface (ENI) is a virtual network interface that you can attach to an instance in a VPC. An ENI can include one public IP address, which can be auto-assigned to the elastic network interface for eth0 when you launch an instance, but only when you_____.

A. create an elastic network interface for eth1
B. include a MAC address
C. use an existing network interface
D. create an elastic network interface for eth0