Answer – B and C
The AWS documentation mentions the following
1. Interface - An elastic network interface with a private IP address that serves as an entry point for traffic destined to a supported AWS service.
2. Gateway - A gateway that is a target for a specified route in your route table, used for traffic destined to a supported AWS service
For more information on VPC endpoints, please refer to the below link:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-endpoints.html