MapMySite is setting up a web application in the AWS VPC. The organization has decided to use
an AWS RDS instead of using its own DB instance for HA and DR requirements.
The organization also wants to secure RDS access. How should the web application be setup
with RDS?

A.
Create a VPC with one public and one private subnet. Launch an application instance in the
public subnet while RDS is launched in the private subnet.

B.
Setup a public and two private subnets in different AZs within a VPC and create a subnet group.
Launch RDS with that subnet group.

C.
Create a network interface and attach two subnets to it. Attach that network interface with RDS
while launching a DB instance.

D.
Create two separate VPCs and launch a Web app in one VPC and RDS in a separate VPC and
connect them with VPC peering.

Explanation:
A Virtual Private Cloud (VPC) is a virtual network dedicated to the user’s AWS account. It enables
the user to launch AWS resources, such as RDS into a virtual network that the user has defined.
Subnets are segments of a VPC’s IP address range that the user can designate to a group of
VPC resources based on the security and operational needs.
A DB subnet group is a collection of subnets (generally private) that a user can create in a VPC
and assign to the RDS DB instances. A DB subnet group allows the user to specify a particular
VPC when creating the DB instances. Each DB subnet group should have subnets in at least two
Availability Zones in a given region.
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_VPC.html