An e-commerce business has deployed a web application on Amazon EC2 instances and wants incoming HTTP requests to be evenly distributed across all healthy instances. Which AWS service or resource should they use?

An Application Load Balancer (ALB) is the correct choice because it operates at the application layer (Layer 7 of the OSI model) and is designed to distribute HTTP and HTTPS traffic. It can route requests based on content, host headers, or URL paths, making it ideal for web applications needing intelligent routing and even distribution across healthy EC2 instances. Amazon EC2 Auto Scaling automatically adjusts the number of EC2 instances based on demand but doesn't distribute incoming traffic itself. Gateway Load Balancer is used for deploying, scaling, and managing third-party virtual appliances. Network Load Balancer operates at the transport layer (Layer 4) and is optimized for extreme performance and static IP addresses, making it less suitable for HTTP-specific routing needs than an ALB.