As an API developer, you have just configured an API with the AWS API gateway service. You are testing out the API and getting the below response whenever an action is made to an undefined API resource.
{ “message”: “Missing Authentication Token” }
You want to customize the error response and make it more user-readable. How can you achieve this?

Answer options:

A.By setting up the appropriate method in the API gateway
B.By setting up the appropriate method integration request in the API gateway
C.By setting up the appropriate gateway response in the API gateway
D.By setting up the appropriate gateway request in the API gateway

Answer - C
This is mentioned in the AWS Documentation.
Set up Gateway Responses to Customize Error Responses
If API Gateway fails to process an incoming request, it returns the client an error response without forwarding the request to the integration backend. By default, the error response contains a short descriptive error message. For example, if you attempt to call an operation on an undefined API resource, you receive an error response with the { "message": "Missing Authentication Token" } message. If you are new to API Gateway, you may find it difficult to understand what actually went wrong.
For some of the error responses, API Gateway allows customization by API developers to return the responses in different formats. For the Missing Authentication Token example, you can add a hint to the original response payload with the possible cause, as in this example: {"message":"Missing Authentication Token", "hint":"The HTTP method or resources may not be supported."}.
The documentation clearly mentions how this should be configured. Hence the other options are all invalid.
For more information on the gateway response, please refer to the below URL-
https://docs.aws.amazon.com/apigateway/latest/developerguide/customize-gateway-responses.html