An e-commerce system has multiple applications that need to exchange messages asynchronously. Which AWS service should be used to enable message queuing between these applications?

Amazon Simple Queue Service (SQS) is the correct choice because it is a fully managed message queuing service that enables you to decouple and scale microservices, distributed systems, and serverless applications. It allows applications to send, store, and receive messages asynchronously, which is ideal for the e-commerce system's requirement to exchange messages between multiple applications without direct, real-time coordination. AWS Auto Scaling automatically adjusts compute capacity to maintain application availability, but it doesn't handle message queuing. Elastic Load Balancing distributes incoming application traffic across multiple targets, focusing on load distribution rather than asynchronous messaging. Amazon Kinesis Data Streams is designed for real-time processing of large streams of data, which is overkill for simple asynchronous message exchange between applications.