Your current architecture consists of a set of web servers spun up as part of an Autoscaling group. These web servers then communicate with a set of database servers. You need to ensure that the database servers` security groups are set properly to accept traffic from the web servers. Which of the following is the best way to accomplish this?

Answer options:

A.Ensure that the Private IP addresses of the web servers are put as sources for the incoming rules in the database server security group.
B.Ensure that the Public IP addresses of the web servers are put as sources for the incoming rules in the database server security group.
C.Ensure that the web server security group is placed as the source for the incoming rules in the database server security group.
D.Ensure that the Instance ID of the web servers are put as sources for the incoming rules in the database server security group.

Answer – C
The below example from the AWS Documentation also shows the Source of the database security group involving the web server security groups` ID.Options A and B are invalid or not the best practice. Since they are part of the Autoscaling Group, the IP addresses of the instances can change.
Option D is incorrect since normally you don’t specify the Instance ID in Security Groups.
For more information on the Security Groups for the VPC, please refer to the below URL-
https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Scenario2.html