The correct options are Amazon API Gateway and AWS Lambda. Amazon API Gateway provides the client facing entry point and AWS Lambda executes application code so that no servers are managed directly.

The Amazon API Gateway service accepts HTTP and WebSocket requests from clients and routes them to backend integrations or invokes AWS Lambda functions. The AWS Lambda service runs code on demand and scales automatically so developers do not provision or manage servers for request handling.

AWS Step Functions coordinates and sequences serverless components and workflows but it is not the primary entry point for end user HTTP or WebSocket traffic.

Amazon DynamoDB is a serverless key value and document database used to store application data and it is not a client facing API endpoint for serving web requests.

Amazon EFS provides managed shared file storage for compute services and it does not expose an HTTP or WebSocket entry point for application clients.

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