Which of the following is the Elastic IP a property of?

Answer options:

A.Elastic Network Interface
B.Subnet
C.CloudTrail
D. MAC Address

Answer - A
The AWS documentation mentions the following
An Elastic IP address is a property of network interfaces. You can associate an Elastic IP address with an instance by updating the network interface attached to the instance.
For more information on Elastic IP’s, please refer to the below link:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-eips.html