What is the scope of an EC2 EIP?

What is the scope of an EC2 EIP?

A.
Placement Group

B.
Availability Zone

C.
Region

D.
VPC

Explanation:
An Elastic IP address is tied to a region and can be associated only with an instance in the same region.
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/resources.html