Which statements are true regarding system-partitioned tables？（）  

• A、 Only a single partitioning key column can be specified.
• B、 All DML statements must use partition-extended syntax.
• C、 The same physical attributes must be specified for each partition.
• D、 Unique local indexes cannot be created on a system-partitioned table.
• E、 Traditional partition pruning and partitionwise joins are not supported on these tables.