You are an Enterprise administrator for contoso.com. The network of your company contains 4,000 client computers located on a single subnet and two DHCP servers. The DHCP servers are named DHCP1 and DHCP2. A router that has a single IP address on the internal interface separates the internal network from the Internet.
DHCP1 has the following scope information.
Starting IP address: 172.16.0.1
Ending IP address: 172.16.15.255
Subnet mask: 255.255.224.0
You need to configure DHCP2 in such a way that the network gets a fault-tolerant DHCP infrastructure and all client computers are be able to obtain a valid IP address if a DHCP server fails.
Which of the following options would you choose to configure the DHCP2?

A.
Create a scope for the subnet 172.16.8.0/19. Configure the scope to use a starting IP address of 172.16.16.1 and an ending IP address of 172.16.31.254.

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 172.16.0.0/20. Configure the scope to use a starting IP address of 172.16.8.1 and an ending IP address of 172.16.15.254.

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.

E.
None of the above

Explanation:

The subnet mask 255.255.224.0 means a /19 subnet. For load balancing you need to ensure that the DHCP2 should be configured on the same network therefore, you need to select answer A where the subnet is 172.16.0.0/19.
The /19 network can contain IP address range from 172.16.0.1 to 172.16.31.255, which means 8190 total hosts can be configured. DHCP1 already contains the IP address range from 172.16.0.1 to 172.16.15.255 to serve 4000 hosts.
In case of the failure of DHCP1, another IP address range is required for the 4000 computers that the network has. Therefore DHCP2 can contain the range of 172.16.16.1 to 172.16.31.254