A company needs to optimize the cost of its application on AWS. The application uses AWS Lambda functions and Amazon Elastic Container Service (Amazon ECS) containers that run on AWS Fargate. The application is write-heavy and stores data in an Amazon Aurora MySQL database. The load on the application is not consistent. The application experiences long periods of no usage, followed by sudden and significant increases and decreases in traffic. The database runs on a memory optimized DB instance that cannot handle the load. A solutions architect must design a solution that can scale to handle the changes in traffic. Which solution will meet these requirements MOST cost-effectively?