In Amazon CloudFront, if you use Amazon EC2 instances and other custom origins with CloudFront, it is recommended to_____.

In Amazon CloudFront, if you use Amazon EC2 instances and other custom origins with CloudFront, it is recommended to_____.
A . not use Elastic Load Balancing
B . restrict Internet communication to private instances while allowing outgoing traffic
C . enable access key rotation for CloudWatch metrics
D . specify the URL of the load balancer for the domain name of your origin server

Answer: D

Explanation:

In Amazon CloudFront, you should use an Elastic Load Balancing load balancer to handle traffic across multiple Amazon EC2 instances and to isolate your application from changes to Amazon EC2 instances. When you create your CloudFront distribution, specify the URL of the load balancer for the domain name of your origin server.

Reference: http://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/CustomOriginBestPractices.html