Correct answer - "Lambda Authorizer" : An Amazon API Gateway Lambda authorizer (formerly known as
a custom authorizer) is a Lambda function that you provide to control access to your API. A
Lambda authorizer uses bearer token authentication strategies, such as OAuth or SAML. Before
creating an API Gateway Lambda authorizer, you must first create the AWS Lambda function that
implements the logic to authorize and, if necessary, to authenticate the caller.
Incorrect:
"IAM permissions with sigv4" - You will still need to provide permissions but our requirements
have need for 3rd party authentication which is where Lambda Authorizer comes in to play
"Cognito User Pools" - This is managed by AWS therefore does not meet our requirements