单项选择题
A.select p.prod_name，p.profit from （select prod_name，profit from profits order by profit desc）where rownum ＜=5；
B.select p.prod_name，p.profit from （select prod_name，sum（profit）from profits group by prod_name order by sum（profit）desc）subq where p.prod_name =subq.prod_name；
C.select p.prod_name，p.profit from （select prod_name，sum（profit）from profits group by prod_name order by sum（profit）desc）where rownum ＜=5；
D.select p.prod_name，p.profit from （select prod_name，sum（profit）from profits order by sum（profit）desc）where rownum ＜=5；
