Which two statements correctly describe the relation between a data file and the logical databasestructures（）

• A、An extent cannot spread across data files.
• B、A segment cannot spread across data files.
• C、A data file can belong to only one tablespace.
• D、A data file can have only one segment created in it.
• E、A data block can spread across multiple data files as it can consist of multiple operating system （OS） blocks.