Which design meets these requirements while minimizing costs?

A three-tier application is being created to host small news articles. The application is expected to serve millions of users. When breaking news occurs, the site must handle very large spikes in traffic without significantly impacting database performance.

Which design meets these requirements while minimizing costs?
A . Use Auto Scaling groups to increase the number of Amazon EC2 instances delivering the web application
B . Use Auto Scaling groups to increase the size of the Amazon RDS instances delivering the database
C . Use Amazon DynamoDB strongly consistent reads to adjust for the increase in traffic
D . Use Amazon DynamoDB Accelerator (DAX) to cache read operations to the database

Answer: D

Explanation:

DAX has in memory cache. If breaking news happens, majority of the users searching will look for the exact same thing. That being said, requests will query the Memory Cache first and will not need to fetch the data from the DB directly.