Which feature best describes AWS Step Functions?

AWS Step Functions is a visual workflow service designed for building serverless applications. It enables developers to coordinate multiple AWS services into serverless workflows, allowing for the automation of processes and management of complex application logic. By using a visual interface, users can define state machines that represent the flow of their application, making it easier to understand and manage the various steps involved in data processing, service orchestration, and application workflows.

This capability significantly enhances the development process by providing error handling, retry logic, and parallel processing out of the box, which contributes to the resilience and reliability of serverless applications. The emphasis on visual representation means that users can see the entire process and understand it dynamically, facilitating easier debugging and iteration.

The other choices reflect features associated with different AWS services but do not capture the essence of Step Functions, which is specifically tailored for orchestrating tasks through a visual workflow mechanism in serverless environments.