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

Explanations:

Using an Application Load Balancer with Amazon ECS requires managing the underlying EC2 instances, which increases operational overhead compared to serverless solutions. ECS also requires scaling configurations that may lead to latency issues during peak times if not managed properly.

Amazon API Gateway combined with AWS Lambda functions with provisioned concurrency allows for automatic scaling, low-latency responses, and minimal operational overhead. Provisioned concurrency ensures that a set number of Lambda instances are always ready to handle requests, which is ideal for handling peak usage.

Using an Application Load Balancer with Amazon EKS requires managing a Kubernetes cluster, which involves significant operational overhead, including scaling, monitoring, and updating the cluster. This option does not provide the low-latency response and ease of management offered by serverless solutions like Lambda.

While Amazon API Gateway with AWS Lambda functions using reserved concurrency can provide consistent performance, it requires more management than provisioned concurrency, as the capacity must be manually adjusted. This increases operational overhead compared to option B, which provides better scalability with lower maintenance.