Migrate contest entry storage to Amazon DynamoDB, establish a DynamoDB Accelerator (DAX) cluster, and refactor the code to operate as Amazon Elastic Container Service (Amazon ECS) containers using the Fargate launch type. Upon contest completion, the DynamoDB table should be deleted.

Shift contest entry storage to Amazon Redshift, rewrite the code as AWS Lambda functions, and delete the Redshift cluster after the contest ends.

Introduce an Amazon ElastiCache for Redis cluster in front of the RDS DB instances to cache contest entries, refactor the code to run as Amazon Elastic Container Service (Amazon ECS) containers using the Fargate launch type, and set the ElastiCache TTL attribute to expire entries at the end of each contest.

Transition contest entry storage to Amazon DynamoDB, rewrite the code as AWS Lambda functions, and set the DynamoDB TTL attribute to automatically expire entries at the end of each contest.