问题：

[单选]

You are the network administrator for Tailspin Toys. The company has a main office and two branch offices. The network in the main office contains 10 servers and 100 client computers. Each branch office contains 5 servers and 50 client computers. Each branch office is connected to the main office by a direct T1 line.  
The network design requires that company IP addresses must be assigned from a single classful private IP address range. The network is assigned a class C private IP address range to allocate IP addresses for servers and client computers.  Tailspin Toys acquires a company named Wingtip Toys. The acquisition will increase the number of servers to 20 and the number of client computers to 200 in the main office. The acquisition is expected to increase the number of servers to 20 and the number of client computers to 200 in the branch offices. The acquisition will also add 10 more branch offices. After the acquisition， all branch offices will be the same size. Each branch office will be connected to the main office by a direct T1 line. The new company will follow the Tailspin Toys network design requirements.  
You need to plan the IP addressing for the new company. You need to comply with the network design requirement.  
What should you do？  （）

A .  Assign the main office and each branch office a new class A private IP address range.
B .  Assign the main office and each branch office a new class B private IP address range.
C .  Assign the main office and each branch office a subnet from a new class B private IP address range.
D .  Assign the main office and each branch office a subnet from the current class C private IP address range.