A Company Wants to Run a Serverless Application on AWS

A company wants to run a serverless application on AWS. The company plans to provision its application in Docker containers running in an Amazon ECS cluster. The application requires a MySQL database and the company plans to use Amazon RDS. The company has documents that need to be accessed frequently for the first 3 months, and rarely after that. The document must be retained for 7 years. What is the MOST cost-effective solution to meet these requirements?

A) Create an ECS cluster using On-Demand Instances. Provision the database and its read replicas in Amazon RDS using Spot Instances. Store the documents in an encrypted EBS volume, and create a cron job to delete the documents after 7 years.
B) Create an ECS cluster using a fleet of Spot Instances, with Spot Instance draining enabled. Provision the database and its read replicas in Amazon RDS using Reserved Instances. Store the documents in a secured Amazon S3 bucket with a lifecycle policy to move the documents that are older than 3 months to Amazon S3 Glacier, then delete the documents from Amazon S3 Glacier that are more than 7 years old.
C) Create an ECS cluster using On-Demand Instances. Provision the database and its read replicas in Amazon RDS using On-Demand Instances. Store the documents in Amazon EFS. Create a cron job to move the documents that are older than 3 months to Amazon S3 Glacier. Create an AWS Lambda function to delete the documents in S3 Glacier that are older than 7 years.
D) Create an ECS cluster using a fleet of Spot Instances with Spot Instance draining enabled. Provision the database and its read replicas in Amazon RDS using On-Demand Instances. Store the documents in a secured Amazon S3 bucket with a lifecycle policy to move the documents that are older than 3 months to Amazon S3 Glacier, then delete the documents in Amazon S3 Glacier after 7 years.