Explanation

Elastic Load Balancer (ELB) is the AWS service specifically designed for distributing incoming application traffic across multiple EC2 instances. Here's why:

• AutoScaling is primarily for automatically adjusting the number of EC2 instances based on demand, not for traffic distribution
• VPC (Virtual Private Cloud) provides network isolation and connectivity, but doesn't handle traffic distribution
• Subnets are logical subdivisions of VPCs for organizing network resources, not for load balancing

Key ELB Features:

• Distributes traffic across multiple EC2 instances in multiple Availability Zones
• Increases fault tolerance of applications
• Automatically detects unhealthy instances and routes traffic only to healthy ones
• Supports various load balancing algorithms

According to AWS documentation: "A load balancer distributes incoming application traffic across multiple EC2 instances in multiple Availability Zones. This increases the fault tolerance of your applications. Elastic Load Balancing detects unhealthy instances and routes traffic only to healthy instances."