Answer: By invoking an AWS Lambda function

**Explanation:** Amazon Lex chatbots use AWS Lambda functions to handle backend processing when all required slot values are filled and an action needs to be executed. Here's why: 1. **Lambda Integration**: Amazon Lex is designed to integrate seamlessly with AWS Lambda functions for fulfillment activities. When a user provides all necessary information (slot values), Lex can invoke a Lambda function to process the request. 2. **Fulfillment Process**: In Lex, fulfillment refers to the process of executing the business logic after all required slots are filled. This typically involves: - Validating the collected information - Performing database operations - Calling external APIs - Executing the requested action (like booking an appointment) 3. **Why Not Other Options**: - **S3**: While S3 can store data, it doesn't execute processing logic - **SNS**: SNS is for messaging and notifications, not for executing business logic - **EC2**: EC2 instances are for running applications, but Lex doesn't directly launch EC2 instances for fulfillment 4. **Workflow**: The typical workflow is: - User provides all required information to Lex - Lex validates the slot values - Lex invokes the configured Lambda function - Lambda function executes the business logic - Lambda returns the result to Lex - Lex provides the response to the user This architecture allows for serverless, scalable backend processing that can handle various business requirements without managing infrastructure.

Author: Jin H