The correct answer is D. To securely configure a custom domain name with Amazon API Gateway, you need to create a Regional API Gateway endpoint and associate it with your domain name. You must import the public certificate associated with your domain name into AWS Certificate Manager (ACM) in the us-east-1 Region, as API Gateway only supports ACM certificates from us-east-1 for custom domain names. Attach this certificate to the API Gateway APIs, and then create Route 53 DNS records pointing an A record to your company's domain name to route the traffic correctly.