Which three statements are true concerning logical and physical database structures? (Choose three.)

A. All tablespaces may have one or more data files

B. The extents of a segment must always reside in the same datafile

C. A smallfile tablespace might be bigger than a bigfile tablespace

D. A segment can span multiple data files in some tablespaces

E. A segment’s blocks can be of different sizes

F. A segment might have only one extent

G. Segments can span multiple tablespsaces

Source：cuug