Which three tasks can be performed using regular expression support in Oracle Database 10g?

Which three tasks can be performed using regular expression support in Oracle Database 10g?
(Choose three.)

A.
it can be used to concatenate two strings.

B.
it can be used to find out the total length of the string.

C.
it can be used for string manipulation and searching operations.

D.
it can be used to format the output for a column or expression having string data.

E.
it can be used to find and replace operations for a column or expression having string data.