You need to ensure that the client computers can obtain IPv4 addresses from DC1

Your network contains an Active Directory domain named contoso.com. The domain
contains a domain controller named DC1 that runs Windows Server 2012 R2. DC1 has the
DHCP Server server role installed.
DHCP is configured as shown in the exhibit. (Click the Exhibit button.)

You discover that client computers cannot obtain IPv4 addresses from DC1.
You need to ensure that the client computers can obtain IPv4 addresses from DC1.
What should you do?

A.
Activate the scope.

B.
Authorize DC1.

C.
Disable the Allow filters.

D.
Disable the Deny filters.

Explanation:
There is no items in the deny List. So it means that client computers MAC addresses is not
listed in the allow list. So we have to disable the “Allow Filters”
http://technet.microsoft.com/en-us/library/ee956897(v=ws.10).aspx