A company is running a web application that has a high amount of dynamic content. The application has MySQL as its database. The company is looking to implement a caching solution for clients requesting the application. What is the best possible solution and why?

Answer options:

A.Offload the DNS to Route 53; Route 53 has DNS servers worldwide and routes the request to the closest region which reduces DNS latency.
B.Create an ElastiCache cluster, write code that caches the correct dynamic content and places it in front of the RDS dynamic content. This will reduce the amount of time it takes to request the dynamic content since it is cached.
C.Create a CloudFront distribution, enable query string forwarding and set the TTL to 0. This will keep TCP connections live from CloudFront to the origin, reducing the time it takes for a TCP handshake to occur.
D.Create a CloudFront distribution, disable query string forwarding and set the TTL to 0. This will keep TCP connections live from CloudFront to the origin, reducing the time it takes for a TCP handshake to occur.

Answer – B
The scenario requires a caching solution which should help to reduce the load time of the dynamic content. ElastiCache is the proper caching solution for this use case.
Option A is INCORRECT because Route 53 helps improving the resolving of the DNS queries for the multi-region application. It does not help caching of the dynamic content.
Option B is CORRECT because ElastiCache is most suited for caching dynamic content. This will make sure the read-intensive load is reduced on the database instance.
Option C is INCORRECT because setting the TTL to 0 in CloudFront does not cache content and is not suited for caching dynamic content.
Option D is INCORRECT because it is the same answer as above, except query string forwarding is disabled. This would block the dynamic content generated at the origin server using the query string parameters.
https://aws.amazon.com/blogs/aws/amazon-cloudfront-support-for-dynamic-content/