Review the following code:
SELECT pn, vn, sum(prc*qty)
FROM sale
GROUP BY CUBE(pn, vn)
ORDER BY 1, 2, 3;
Which combination of subtotals do you expect to be returned by the query?
A . (pn, vn)
B . ( (pn, vn), (pn) )
C . ( (pn, vn) , (pn), (vn) )
D . ( (pn, vn) , (pn), (vn) , ( ) )
Answer: D