A network architect at a global financial institution overhauls the company$$s on$-$premises network to enhance security and reduce the attack surface. To accomplish this, the architect assesses various architecture models and their respective impact on the on$-$premises network$$s security implications. While redesigning the on$-$premises network, which architecture derivative$/$model could effectively decrease the attack surface?

a$.$

Peer$-$to$-$peer network

b$.$

Hybrid cloud

c$.$

Content delivery networks

d$.$

Centralized architecture