Which solution will meet these requirements with the LEAST operational overhead?

Explanations:

While using Amazon CloudFront and AWS Amplify for hosting the static frontend is a good choice, migrating the MySQL database to an EC2 Reserved Instance does not provide the operational overhead reduction required for a globally available solution. Using EC2 requires managing the instance and maintenance, which increases operational overhead compared to managed services like Amazon RDS. Additionally, refactoring the microservices to AWS Lambda via API Gateway is good, but the database migration choice is a limiting factor.

This option uses Amazon CloudFront and Amazon S3 for hosting the static web frontend, which provides low latency and high availability globally. Refactoring the microservices to AWS Lambda functions accessed via API Gateway allows for scalable and serverless architecture, reducing operational overhead. Migrating the MySQL database to Amazon RDS for MySQL simplifies database management with automated backups, scaling, and patching, aligning with the goal of ensuring security and availability with minimal operational overhead.

Although this option includes using Amazon CloudFront and S3 for the static frontend and refactoring microservices to Lambda functions, it suggests using a Network Load Balancer (NLB) instead of API Gateway. NLB is typically used for TCP traffic and requires more management than API Gateway, which is designed for HTTP APIs and has built-in security features. This would not minimize operational overhead as effectively as API Gateway. Additionally, using RDS is correct, but the load balancing choice diminishes the overall suitability.

This option suggests using S3 for hosting the static web frontend and AWS Lambda functions behind an Application Load Balancer (ALB). However, using an ALB introduces more complexity and operational overhead compared to using API Gateway, which is more suited for microservice architectures. Furthermore, migrating the MySQL database to an EC2 Reserved Instance means increased management and maintenance overhead, contrary to the requirement for minimal operational overhead.