[单选题]

You have a class C network, and you need to design it for 5 usable subnets with each subnet handling a minimum of 18 hosts each. Which of the following network masks should you use?
A．225.225.224.0.
B．225.225.240.0.
C．225.225.255.0.
D．255.255.255.224
E．225.225.255.240

You have a class C network, and you need to design it for 5 usable subnets with each subnet handling a minimum of 18 hosts each. Which of the following network masks should you use?A．225.225.224.0.B．225.225.240.0.C．225.225.255.0.D．255.255.255.224E．225.225.255.240