Which of the following descriptions fits AWS Lambda best?

AWS Lambda is best described as a serverless compute service that runs code in response to events. This means that it allows developers to execute code in response to specific triggers—such as changes to data in an Amazon S3 bucket or updates in a DynamoDB table—without having to provision or manage servers. The serverless design abstracts the underlying infrastructure, enabling users to focus solely on writing the code that powers their applications.

The event-driven architecture of Lambda means that the code runs automatically when the defined event occurs, making it highly scalable and efficient for numerous applications. This model aligns with the modern approach of microservices and API-driven designs, where applications can react to a variety of events dynamically.

In contrast, other options describe different AWS services. The first option refers to a framework for building applications, which doesn’t capture the essence of Lambda being specifically a compute service. The third option describes a managed database service, which is not relevant to Lambda’s role. Lastly, the fourth choice concerns virtual networks, which again is unrelated to the functionality of Lambda. Thus, the description of a serverless compute service that operates on events accurately encapsulates the unique capabilities of AWS Lambda.