You administer a SQL Server 2008 Reporting Services (SSRS) instance. You plan to design an authentication method for SSRS reports that use SQL Server data connections. You need to ensure that all SSRS reports communicate to the SQL Server instance by using the Kerberos authentication protocol. What should you do?（）

A. Configure the default Web site on the instance to use the Integrated Security type.
B. Configure the application pool used by the default Web site to use a domain account.
Configure the default Web site on the instance to use the Secure Sockets Layer (SSL) protocol.
D. Register a service principal name (SPN) in the Active Directory directory service for the SSRS instance.