Which statement correctly describes the function of Oracle9i Cache Fusion feature？（）

AIt provides each session with its own view of the database at a different point in the past. 

BIt enables you to execute scalable applications on a clustered database without having to partition the users or the database tables. 

CIt lets you dynamically reassign memory in your database buffer cache to different block buffer sizes. 

DIt allows you to add new sites to multimaster replication environment without quiescing the master definition site.