Which is the simplest and MOST secure design to use to build an authentication and authorization model for the APIs?

A company developed a set of APIs that are being served through the Amazon API Gateway. The API calls need to be authenticated based on OpenID identity providers such as Amazon or Facebook. The APIs should allow access based on a custom authorization model.

Which is the simplest and MOST secure design to use to build an authentication and authorization model for the APIs?
A . Use Amazon Cognito user pools and a custom authorizer to authenticate and authorize users based
on JSON Web Tokens.
B . Build a OpenID token broker with Amazon and Facebook. Users will authenticate with these identify providers and pass the JSON Web Token to the API to authenticate each API call.
C . Store user credentials in Amazon DynamoDB and have the application retrieve temporary credentials from AWS ST
D . Make API calls by passing user credentials to the APIs for authentication and authorization.
E . Use Amazon RDS to store user credentials and pass them to the APIs for authentications and authorization.

Answer: A