A company uses API Gateway to invoke a Lambda function. There are separate Lambda versions for PROD and DEV, and each has an alias pointing to its version. API Gateway has one stage pointing to the PROD alias. The company wants API Gateway to expose both PROD and DEV Lambda versions simultaneously and distinctly. Which approach satisfies this requirement?

The correct approach is to use API Gateway stage variables. By creating a new API Gateway stage for DEV and configuring a stage variable in each stage (PROD and DEV) to point to its respective Lambda alias, you can expose both versions simultaneously and distinctly. API Gateway will then use the stage variable to determine which Lambda alias to invoke based on the stage being accessed. Incorrect options: Lambda authorizers are for authentication/authorization, not for routing to different Lambda versions. Gateway responses are for customizing error responses, not for routing requests to different backends. Environment variables in API Gateway are typically used for configuration within the API Gateway itself or passed to the backend, but they don't directly control which Lambda alias a stage invokes in this manner. Stage variables are specifically designed for stage-specific configurations like backend endpoints.