Which two statements are true about associative arrays and nested tables?

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

A.
Only associative arrays can hold an arbitrary number of elements.

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

C.
Both associative arrays and nested tables can hold an arbitrary number of elements.

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