A Bank Is Experiencing a DoS Attack Against an Application

A bank is experiencing a DoS attack against an application designed to handle 500 IP-based sessions. in addition, the perimeter router can only handle 1Gbps of traffic. Which of the following should be implemented to prevent a DoS attacks 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