A company is using AWS to develop and manage its production web application. The application includes an Amazon API Gateway HTTP API that invokes an AWS Lambda function. The Lambda function…

Option A correctly identifies that API Gateway can integrate with a third-party identity provider and validate OAuth tokens directly through its built-in authorization mechanisms, such as JWT authorizers for HTTP APIs or custom (Lambda) authorizers, providing a seamless and integrated authorization solution.

AWS Directory Service is primarily for managing directory services and is not the direct, integrated solution for authorizing API Gateway requests with OAuth tokens from an external IdP.

AWS IAM Identity Center (successor to AWS SSO) is for centralized access management to AWS accounts and applications, but API Gateway does not directly use it as an authorizer for API requests.

IAM Identity Center focuses on user access to AWS resources and applications, but configuring IAM roles alone would not directly integrate with the third-party OAuth tokens for API Gateway request authorization.