The Cisco Unity server is being upgraded from version 4.21 to version 5.0 with Exchange Server 2003 as the message store. Which two steps ensure a successful upgrade? (Choose two.)

A.
Remove Windows 2000 and install Windows 2003.

B.
Run the Database Optimizer to ensure a “clean” database.

C.
Run the Active Directory Schema Extension Utility.

D.
Run the Cisco Unity System Preparation Assistant.

E.
Run the Cisco Unity Upgrade Tool.