Your network contains two Active Directory forests named contoso.com and adatum.com.
Contoso.com contains one domain. Adatum.com contains a child domain named
child.adatum.com.
Contoso.com has a one-way forest trust to adatum.com. Selective authentication is enabled
on the forest trust.
Several user accounts are migrated from child.adatum.com to adatum.com.
Users report that after the migration, they fail to access resources in contoso.com. The users
successfully accessed the resources in contoso.com before the accounts were migrated.
You need to ensure that the migrated users can access the resources in contoso.com.
What should you do?

A.
Replace the existing forest trust with an external trust.

B.
Run netdom and specify the /quarantine attribute.

C.
Disable SID filtering on the existing forest trust.

D.
Disable selective authentication on the existing forest trust.

Explanation:
A)

B)
Enables administrators to manage Active Directory domains and trust relationships from
the command prompt, /quarantine Sets or clears the domain quarantine
C)
Need to gain access to the resources in contoso.com
D)
Selective authentication over a forest trust restricts access to only those users in a trusted
forest who have been explicitly given authentication permissions to computer objects
(resource computers) that reside in the trusting forest
http://technet.microsoft.com/en-us/library/cc755321(v=ws.10).aspx
http://technet.microsoft.com/en-us/library/cc758152(v=ws.10).aspx