Your team is experimenting with the API gateway service for an application. There is a need to implement a custom module that can be used for authentication/authorization for calls made to the API gateway. How can this be achieved?

Answer options:

A.Enable API gateway caching.
B.Use a Lambda authorizer.
C.Use API endpoint.
D.Use CORS on the API gateway.

Answer: B
Option A is incorrect because API caching helps to reduce the number of calls made to your endpoint and improves the latency of requests to your API but cannot assist with authentication/authorization for calls made to the API gateway.
Option B is CORRECT because Amazon API Gateway Lambda authorizer (formerly known as a custom authorizer) is a Lambda function that you provide to control access to your API methods. A Lambda authorizer uses bearer token authentication strategies, such as OAuth or SAML. It can also use the information described by headers, paths, query strings, stage variables, or context variables request parameters.
Option C is incorrect because the API endpoint refers to the hostname of the API. The API endpoint type can be edge-optimized, regional, or private, depending on where the majority of your API traffic originates from, but it cannot assists with authentication/authorization for calls made to the API gateway.
Option D is incorrect because Cross-origin resource sharing (CORS) is a browser security feature that restricts cross-origin HTTP requests initiated from scripts running in the browser, but it cannot assist with authentication/authorization for calls made to the API gateway.
For more information on using the API gateway Lambda authorizer, kindly refer to the following URL:
https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-use-lambda-authorizer.html