You are currently hosting multiple applications in a VPC and have logged numerous port scans coming in from
a specific IP address block. Your security team has requested that all access from the offending IP address
block be denied for the next 24 hours.
Which of the following is the best method to quickly and temporarily deny access from the specified IP address
block?

A.
Create an AD policy to modify Windows Firewall settings on all hosts in the VPC to deny access from the IP
address block

B.
Modify the Network ACLs associated with all public subnets in the VPC to deny access from the IP address
block

C.
Add a rule to all of the VPC 5 Security Groups to deny access from the IP address block

D.
Modify the Windows Firewall settings on all Amazon Machine Images (AMIs) that your organization uses in
that VPC to deny access from the IP address block

Explanation:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_SecurityGroups.html