Select a true statement about Amazon EC2 Security Groups (EC2-Classic).

Select a true statement about Amazon EC2 Security Groups (EC2-Classic).
A .  After you launch an instance in EC2-Classic, you can’t change its security groups.
B .  After you launch an instance in EC2-Classic, you can change its security groups only once.
C .  After you launch an instance in EC2-Classic, you can only add rules to a security group.
D .  After you launch an instance in EC2-Classic, you cannot add or remove rules from a security group.

View Answer

Answer: A

Explanation:

After you launch an instance in EC2-Classic, you can’t change its security groups.

However, you can add rules to or remove rules from a security group, and those changes are automatically applied to all instances that are associated with the security group.

Reference: http://docs.amazonwebservices.com/AWSEC2/latest/UserGuide/using-network-security.html