A user has launched an EC2 instance and installed a website with the Apache webserver. The webserver is running but
the user is not able to access the website from the internet. What can be the possible reason for this failure?

A.
The security group of the instance is not configured properly.

B.
The instance is not configured with the proper key-pairs.

C.
The Apache website cannot be accessed from the internet.

D.
Instance is not configured with an elastic IP.

Explanation:
In Amazon Web Services, when a user has configured an instance with Apache, the user needs to ensure that the ports
in the security group are opened as configured in Apache config. E.g. If Apache is running on port 80, the user should
open port 80 in the security group.

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-network-security.html