Your web application consists of 10% writes and 90% reads. You currently service all requests through a Route53 Alias Record directed towards an AWS ELB, which sits in front of an EC2 Auto Scaling Group. Your system is getting very expensive when there are large read traffic spikes during certain news events, during which many more people access your web application, all at the same time. What is the simplest and cheapest way to reduce costs and scale with spikes like this?

Answer options:

A.Create an S3 bucket and asynchronously replicate common request responses into S3 objects. When a request comes in for a pre-computed response, redirect to AWS S3.
B.Create another ELB and Auto Scaling Group layer mounted on top of the other system, adding a tier to the system. Serve most read requests out of the top layer.
C.Create a CloudFront Distribution and direct Route53 to the Distribution. Use the ELB as an Origin and specify Cache Behaviours to proxy cache requests.
D.Create a Memcached cluster in AWS ElastiCache. Create cache logic to serve requests which can be served late from the in-memory cache for increased performance.

Answer – C
Use CloudFront distribution for distributing the heavy reads for your application. You can create a zone apex record to point to the CloudFront distribution.
You can control how long your objects stay in a CloudFront cache before CloudFront forwards another request to your origin. Reducing the duration allows you to serve dynamic content. Increasing the duration means your users get better performance because your objects are more likely to be served directly from the edge cache. A longer duration also reduces the load on your origin.
For more information on CloudFront object expiration, please visit the below URL:
http://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Expiration.html