Your Company Has 500 Branch Sites and the CIO Is

Your company has 500 branch sites and the CIO is concerned about minimizing the potential impact of a VPN router being stolen from an enterprise branch site. You want the ability to quickly disable a stolen VPN router while minimizing administrative overhead. Which solution accomplishes this task?

A) Implement a certificate-based VPN using a public key infrastructure (PKI)
B) Modify your IKE proposals to use Diffie-Hellman group 14 or higher
C) Use firewall filters to block traffic from the stolen VPN router
D) Rotate VPN pre-shared keys every month