In Amazon Elastic Compute Cloud, which of the following is used for communication between instances in the same network (EC2-Classic or a VPC)?

In Amazon Elastic Compute Cloud, which of the following is used for communication between instances in the same network (EC2-Classic or a VPC)?
A . Private IP addresses
B . Elastic IP addresses
C . Static IP addresses
D . Public IP addresses

Answer: A

Explanation:

A private IP address is an IP address that’s not reachable over the Internet. You can use private IP addresses for communication between instances in the same network (EC2-Classic or a VPC).

Reference: http://docs.amazonwebservices.com/AWSEC2/latest/UserGuide/using-instance-addressing.html