Your application is deployed in EC2 instances and uses CloudFront to deliver the content. In order to reduce the cost of requests to the origin, you plan to increase the cache duration in CloudFront for certain dynamic contents. Which of the following options is the most appropriate to achieve the requirement?

Answer options:

A.Modify the application to add a Cache-Control header to control how long the objects stay in the CloudFront cache.
B.In the CloudFront distribution, enlarge the default TTL in the object caching setting
C.Specify the minimum TTL to be 0 in the CloudFront object caching setting.
D.Add a Cache-Control header by configuring the metadata of the S3 objects.

Correct Answer – A
Option A is CORRECT: Because the Cache-Control header added by the origin server can be used to control the caching behavior in CloudFront. The application is responsible for adding the header for individual objects.
Option B is incorrect: Because the default TTL impacts all objects if the origin does not add the cache header. However, in the question, only certain dynamic contents need to be modified.
Option C is incorrect: Because the cache duration is not increased by setting the value of Minimum TTL to be 0. Please check the below reference on how to determine the amount of time that CloudFront keeps an object in the cache.
Option D is incorrect: The question mentions that the cache duration of dynamic contents needs to be increased. However, S3 objects belong to static contents.
Reference:
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Expiration.html.