How should the following UDF be invoked in order to convert US currency values stored in the EXPENSE

How should the following UDF be invoked in order to convert US currency values stored in the
EXPENSES table into Canadian currency?
CREATE FUNCTION getratews11 (
country1 VARCHAR(100),
country2 VARCHAR(100) )
RETURNS DOUBLE
LANGUAGE SQL
CONTAINS SQL
EXTERNAL ACTION NOT DETERMINISTIC
BEGIN
…
END

A.
CALLgetratews11(‘USA’,’CANADA’)

B.
CALLexpenses.getratews11(‘USA’,’CANADA’)

C.
SELECTgetratews11(‘USA’,’CANADA’) FROM expenses

D.
SELECT * FROMTABLE(getratews11(‘USA’,’CANADA’)) AS convert_currency