A company runs a microservice-based serverless web application.

An edge-optimized API Gateway is a way to create RESTful APIs that can access multiple DynamoDB tables through AWS Lambda functions. The edge-optimized API Gateway provides low latency and high performance by caching API responses at CloudFront edgelocations. The AWS Lambda functions can use the AWS SDK to query or scan the DynamoDB tables and return the data to the API Gateway. This solution meets all the requirements of the question, while the other options do not. References:

https://aws.amazon.com/blogs/compute/understanding-database-options-for-your-serverless-web-applications/

https://aws.amazon.com/getting-started/hands-on/build-serverless-web-app-lambda-apigateway-s3-dynamodb-cognito/module-3/

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/best-practices.html