A Company ABC has 100 REST APIs exposed to the Internet from their on-premise network. They have already integrated with AWS through DirectConnect. They have approached you asking for a cost-effective way of making these REST APIs available through AWS API Gateway because of the resiliency and cost reductions provided by it. What solution would you provide?

Answer options:

A.API Gateway cannot integrate with on-premises backend APIs which are not over the public internet. Rebuild all the backend APIs using Lambda and integrate it with API Gateway.
B.Use VPC Link to integrate on-premises backend solutions through DirectConnect and private VPC.C.Build API Gateway using the existing on-premises public facing REST APIs as HTTPS endpoints integration type.
D.Build API Gateway with integration type as AWS Service and select Direct Connect service.

Answer: B 
For more information on VPC Link, refer to the documentation here. 
https://aws.amazon.com/blogs/compute/introducing-amazon-api-gateway-private-endpoints/
Option A is INCORRECT because you can use API Gateway to integrate with on-premises backend APIs. Therefore this option is invalid.
Option C is INCORRECT because you can choose the integration type as "HTTPS" if your API is integrated with an existing HTTPS endpoint. Since the question does not state any integration with any HTTPS endpoint, this option is invalid.
Option D is INCORRECT because you can choose the integration type as "AWS Service" only if your API will be integrated with an AWS service. Since the question does not state any integration with any AWS service, this option is invalid.
Please refer to page 605 on the below link:
https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-dg.pdf