Which statement about the overlay VPN model is true?
A. The overlay model demands a lot from provisioning because when adding one customer site, it demands many configuration changes at many other routers on the provider side.
B. The overlay model does not scale to the same size as the MPLS VPN model.
C. The overlay model provides the ability to reduce the amount of routing state that core routers need to hold to meet the scalability requirements compared to the MPLS VPN model.
D. The overlay model provides privacy and isolation between the different customers by using packet filters that control the data to and from the customer routers.
