Answer: By invoking an AWS Lambda function

## Explanation Amazon Lex triggers backend processing by invoking AWS Lambda functions. Here's how it works: - **AWS Lambda Integration**: When Lex gathers all required slot values and is ready to fulfill an intent (like "book appointment"), it invokes a Lambda function to process the request. - **Functionality**: The Lambda function contains the business logic to handle the action, such as making database calls, processing data, or integrating with other services. - **Response Handling**: The Lambda function returns a response to Lex, which then sends the appropriate message back to the user. **Why other options are incorrect:** - **B) S3**: S3 is for storage, not for triggering backend processing - **C) SNS**: SNS is for pub/sub messaging, not the primary method for Lex backend processing - **D) EC2**: EC2 instances are for compute, but Lex doesn't launch instances for backend processing This Lambda integration allows Lex to execute complex backend operations while maintaining the conversational flow with users.

Author: Ritesh Yadav