You need to have a Data storage layer in AWS. Following are the key requirements:
a) Storage of documents in JSON file format.
b) Availability of Indexes
c) Automatic scaling
What would be an ideal storage layer for the above requirements?

Answer options:

A.AWS DynamoDB
B.AWS EBS Volumes
C.AWS S3
D.AWS Glacier

Correct Answer – A
AWS Documentation mentions the following.
Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability. DynamoDB enables customers to offload the administrative burdens of operating and scaling distributed databases to AWS. For that, they don’t have to worry about hardware provisioning, setup, and configuration, throughput capacity planning, replication, software patching, or cluster scaling.
- Indexes give you access to alternate query patterns and can speed up queries. This section compares and contrasts index creation and usage in SQL and Amazon DynamoDB.- Amazon DynamoDB auto scaling uses the AWS Application Auto Scaling service to dynamically adjust provisioned throughput capacity on your behalf, in response to actual traffic patterns. This enables a table or a global secondary index to increase its provisioned read and write capacity to handle sudden increases in traffic, without throttling. 
For more information on DynamoDB, please visit the following URL-
https://aws.amazon.com/dynamodb/faqs/
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/AutoScaling.html