Your network contains an Active Directory domain named contoso.com. The functional level of the domain and the functional level of the forest are Windows Server 2003. All domain controllers run Windows Server 2008. You have a member server that runs Windows Server 2008 R2 named Server1. You install the Distributed Scan Server role service on Server1. From the Scan Management console, you attempt to add a scan process and you receive the following error. You need to ensure that you can add a scan process. What should you do？（）

A. Install the Fax Server role.
B. Install the Print Server role service.
C. Update the Active Directory schema.
D. Set the functional level of the forest to Windows Server 2008.