Which configuration represents a valid use of security groups in a virtual private cloud (VPC)?
A. Set a deny rule that prevents access to the subnet from the public internet.
B. Limit outbound traffic from an Amazon EC2 instance in the VPC to a specific database server.
C. Limit inbound access to the private subnet of the VPC.
D. Set a deny rule that prevents outbound traffic from an Amazon EC2 instance in a VPC.