You are a messaging professional. Your company has an Exchange organization that includes Microsoft Exchange Server 2003 computers and Microsoft Exchange Server 2007 computers. The company has a single Microsoft Active Directory forest.

The company acquires a new subsidiary. The subsidiary company has its own Active Directory forest.

The subsidiary company uses an Exchange Server organization that includes Exchange Server 2003 computers and Exchange Server 2007 computers.

Message routing is enabled between the two Exchange organizations.

Users in both the companies report that they cannot view recipients from the other company in the Global Address List (GAL).

You need to ensure that the GAL in both companies has all e-mail recipients of both the Exchange organizations.

What should you do to ensure that the GAL in both companies has all e-mail recipients of both the Exchange organizations?

A.
Configure the Availability service between the two Exchange organizations.

B.
Implement and configure the Microsoft Exchange Server Inter-Organization Replication tool.

C.
Implement a two-way forest trust between the two organizations. Enable forest-wide authentication on the
forest trust.

D.
Implement and configure the Identity Integration Feature Pack (IIFP) to replicate data between the two
Exchange organizations.