A company seeks to optimize the cost of their AWS-based application, which utilizes AWS Lambda functions and Amazon Elastic Container Service (Amazon ECS) containers running on AWS Fargate. The application is characterized by heavy write operations and stores its data in an Amazon Aurora MySQL database. The application's usage pattern is inconsistent, with extended periods of inactivity followed by abrupt spikes and dips in traffic. The current memory-optimized DB instance struggles to manage the load during peak times. A solutions architect is tasked with designing a cost-effective solution that can dynamically scale to accommodate the fluctuating traffic. Which of the following solutions would be the most cost-effective in meeting these requirements?