George Has Launched Three EC2 Instances Inside the US-East-1a Zone

Multiple Choice

George has launched three EC2 instances inside the US-East-1a zone with his AWS account. Ray has launched two EC2 instances in the US-East-1a zone with his AWS account. Which of the below mentioned statements will help George and Ray understand the availability zone (AZ) concept better?

A) The instances of George and Ray will be running in the same data center
B) All the instances of George and Ray can communicate over a private IP with a minimal cost
C) All the instances of George and Ray can communicate over a private IP without any cost
D) The US-East-1a region of George and Ray can be different availability zones