What should you create?

Your network contains two Active Directory forests named contoso.com and adatum.com.
Each forest contains one domain. A two-way forest trust exists between the forests.
The forests use the address spaces shown in the following table.

From a computer in the contoso.com domain, you can perform reverse lookups for the
servers in the contoso.com domain, but you cannot perform reverse lookups for the servers
in the adatum.com domain.
From a computer in the adatum.com domain, you can perform reverse lookups for the
servers in both domains.
You need to ensure that you can perform reverse lookups for the servers in the adatum.com
domain from the computers in the contoso.com domain.
What should you create?

A.
A trust point

B.
A GlobalNames zone

C.
A delegation

D.
A conditional forwarder

Explanation:
Conditional forwarders are DNS servers that only forward queries for specific domain
names. Instead of forwarding all queries it cannot resolve locally to a forwarder, a conditional
forwarder is configured to forward a query to specific forwarders based on the domain name
contained in the query. Forwarding in terms of domain names improves conventional
forwarding by adding a name-based condition to the forwarding process.
References:
http://technet.microsoft.com/en-us/library/cc757172(v=ws.10).aspx