问题：

[单选]

Your network contains two DHCP servers. The DHCP servers are named DHCP1 and DHCP2. The  
internal network contains 1，000 DHCP client computers that are located on a single subnet. A routerseparates the internal network from the Internet. The router has a single IP address on the internal  interface. DHCP1 has the following scope information.
èStarting IP address： 172.16.0.1 
èEnding IP address： 172.16.7.255 
èSubnet mask： 255.255.240.0  
You need to provide a fault-tolerant DHCP infrastructure that supports the client computers on the internal  network. In the event that a DHCP server fails， all client computers must be able to obtain a valid IP  address.
How should you configure DHCP2？（） 

A . Create a scope for the subnet 172.16.0.0/20. Configure the scope to use a starting IP address of  172.16.8.1 and an ending IP address of 172.16.15.254.
B . Create a scope for the subnet 172.16.0.0/21. Configure the scope to use a starting IP address of  172.16.0.1 and an ending IP address of 172.16.15.254.
C . Create a scope for the subnet 172.16.8.0/21. Configure the scope to use a starting IP address of  172.16.8.1 and an ending IP address of 172.16.10.254.
D . Create a scope for the subnet 172.17.0.0/16. Configure the scope to use a starting IP address of  172.17.0.1 and an ending IP address of 172.17.255.254.