Which combination of steps will meet this requirement with the LEAST amount of operational overhead?

Explanations:

Creating an S3 bucket to host static webpages allows the company to easily serve custom error pages. S3 can be configured to host a static website, providing a cost-effective and low-maintenance solution for serving custom error responses.

While creating a CloudWatch alarm and using a Lambda function to modify ALB forwarding rules can potentially redirect traffic, it introduces unnecessary complexity and operational overhead. This approach requires ongoing management of the Lambda function and routing logic, which is not ideal for simply serving custom error pages.

Modifying Route 53 records with health checks and fallback targets is a complex solution for serving custom error pages. It requires management of DNS records and health check configurations, which adds operational overhead. This approach is more suited for failover scenarios rather than just serving custom error pages.

Similar to option B, invoking a Lambda function to modify ALB forwarding rules based on internal error health checks adds unnecessary complexity. This method is more focused on managing routing rather than simply displaying custom error pages.

Configuring CloudFront to use custom error pages allows the company to serve customized responses without modifying the underlying application or the ALB configuration. CloudFront provides built-in support for custom error responses, reducing operational overhead while effectively managing error display.