Your network consists of an Active Directory Domain Services （AD DS） forest with 1，000 client computers that run Windows XP. Nine hundred of the computers are on the local area network. One hundred computers are portable computers that connect to the main office only once every few months. You are planning to deploy Windows 7. You need to generate a report of the software that is installed on all client computers. You need this information as soon as possible. What should you use？（）

A. Microsoft System Center Essentials
B. Microsoft Desktop Optimization Pack
C. Microsoft System Center Operations Manager
D. Microsoft System Center Data Protection Manager