Which statement is true about the PCTFREE setting for the table（）

• A、It sets the minimum percentage of a data block to be reserved to contain chained rows from other blocks.
• B、It sets the minimum percentage of a data block to be reserved as free space before the server prevents inserts into the block.
• C、It sets the minimum percentage of a data block to be reserved to contain the bitmap used to maintain the free block information.
• D、It sets the minimum percentage of a block that can be used for row data plus overhead before new rows are added to the block.