AWS Certified Advanced Networking - Specialty (#33)

The Web Application Development team is worried about malicious activity from 200 random IP addresses. Which action will ensure security and scalability from this type of threat?

Use inbound security group rules to block the IP addresses.
Use inbound network ACL rules to block the IP addresses.
Use AWS WAF to block the IP addresses.
Write iptables rules on the instance to block the IP addresses.