A file-sharing service uses Amazon S3 to store files uploaded by users. Files are accessed with random frequency. Popular ones are downloaded every day whilst others not so often and some rarely. What is the most cost-effective Amazon S3 object storage class to implement?

Answer options:

A.Amazon S3 Standard
B.Amazon S3 Glacier
C.Amazon S3 One Zone-Infrequently Accessed
D.Amazon S3 Intelligent-Tiering

Correct Answer – D
S3 Intelligent-Tiering is a new Amazon S3 storage class designed for customers who want to optimize storage costs automatically when data access patterns change, without performance impact or operational overhead. S3 Intelligent-Tiering is the first cloud object storage class that delivers automatic cost savings by moving data between two access tiers — frequent access and infrequent access — when access patterns change, and is ideal for data with unknown or changing access patterns.
S3 Intelligent-Tiering stores objects in two access tiers: one tier optimized for frequent access and another lower-cost tier optimized for infrequent access. For a small monthly monitoring and automation fee per object, S3 Intelligent-Tiering monitors access patterns and moves objects that have not been accessed for 30 consecutive days to the infrequent access tier. There are no retrieval fees in S3 Intelligent-Tiering. If an object in the infrequent access tier is accessed later, it is automatically moved back to the frequent access tier. No additional tiering fees apply when objects are moved between access tiers within the S3 Intelligent-Tiering storage class. S3 Intelligent-Tiering is designed for 99.9% availability and 99.999999999% durability, and offers the same low latency and high throughput performance of S3 Standard.
https://aws.amazon.com/about-aws/whats-new/2018/11/s3-intelligent-tiering/
Option A is incorrect because Amazon S3 Standard would be an inefficient class for storing those objects that will be accessed rarely.
Option B is incorrect because storing objects that are frequently accessed in Amazon S3 Glacier would present operational bottlenecks since these objects would not be available instantly.
https://aws.amazon.com/s3/storage-classes/
Option C is incorrect because storing those objects that are rarely accessed and those that would be accessed frequently in Amazon S3 One Zone-Infrequently Accessed would be inefficient.