A bank is experiencing a DOS attack against an application designed to handle 500IP-based sessions. In addition, the perimeter router can only handle 1 Gbps of traffic. Which of the following should be implemented to prevent a DOS attack in the future?
A. Deploy multiple web servers and implement a load balancer
B. Increase the capacity of the perimeter router to 10 Gbps
C. Install a firewall at the network to prevent all attacks
D. Use redundancy across all network devices and services