What is the scope of an EBS volume?

What is the scope of an EBS volume?

A.
VPC

B.
Region

C.
Placement Group

D.
Availability Zone

Explanation:
An Amazon EBS volume is tied to its Availability Zone and can be attached only to instances in the same Availability
Zone.
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/resources.html