Which two statements are true about nested tables and varrays?

Which two statements are true about nested tables and varrays? (Choose two.)

A.
Only varrays must have consecutive numbers as subscripts.

B.
Only nested tables can be used as column types in database tables.

C.
Both nested tables and varrays must have consecutive numbers as subscripts.

D.
Both nested tables and varrays can be used as column types in database tables.