Abank 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