Which two actions limit the consequences of a network based attack?

Which two actions limit the consequences of a network based attack?

A.
Implementing the principle of least privilege

B.
Installing a firewall at the outer boundary of your systems

C.
Placing Internet-accessible servers in a demilitarized zone

D.
Deploying a single sign-on system to provide system-wide authorization

E.
Allowing application servers privileged access to all databases