Your network contains an Active Directory forest. The forest schema contains a custom
attribute for user objects.
You need to modify the custom attribute value of 500 user accounts.
Which tool should you use?

A.
Csvde

B.
Dsmod

C.
Dsrm

D.
Ldifde

Explanation:
We cannot use Dsmod here, because it supports only a subset of commonly used object
class attributes.
Csvde can only import and export data.
Dsrm is used to delete objects from the directory.

http://technet.microsoft.com/en-us/library/cc731033.aspx
Ldifde
Creates, modifies, and deletes directory objects.