An Organization has an application using Amazon S3 Glacier to store large CSV objects. While retrieving these large objects end users are observing some performance issue. In most cases, users only need a small part of the data instead of the entire objects. 
A solutions Architect has been asked to re-design this solution to improve the performance. Which solution is the most cost-effective?

Answer options:

A.Use AWS Athena to retrieve only the data that users need.
B.Use S3 Select to retrieve only the data that users need.
C.Use Glacier Select to retrieve only the data that users need.
D.Use custom SQL statements and S3 APIs to retrieve only the data that users need.

Correct Answer : C
Option A is incorrect because Athena supports standard SQL to retrieve data, but it`s more used for analytical data.
Option B is incorrect because the objects are stored in Glacier. The correct method should be Glacier Select.
Option C is CORRECT because the application needs to retrieve data from Glacier. With Glacier Select, you can perform filtering directly against a Glacier object using standard SQL statements.
Option D is incorrect because writing custom SQL statements with S3 APIS wouldn`t improve performance.
 Reference:
https://aws.amazon.com/blogs/aws/s3-glacier-select/