If you want to have a cluster of EC2 Instances which would need to have low network latency between them , which of the following would you ideally do.

Answer options:

A.Launch all of the Instances as t2.micro instances
B.Launch all of the instances with Security Groups which allows all network traffic
C.Launch all of the instances with NACL’s which allows all network traffic
D.Launch all of the instances in a placement group

Answer – D
The AWS documentation mentions the following
A placement group is a logical grouping of instances within a single Availability Zone. Placement groups are recommended for applications that benefit from low network latency, high network throughput, or both. To provide the lowest latency, and the highest packet-per-second network performance for your placement group, choose an instance type that supports enhanced networking.
For more information on placement groups, please refer to the below link:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html