area of the down sprue

Question

A 200 mm long down sprue has n area of cross secion of 650 $mm^{2}$, where the pouring basin meets the down sprue (i.e. at the beginning of a down sprue). A constand head of molten metal is maintaining by the pouring basin. The molten metal flow rate is 6.5 ´ 10⁵ mm³/s. considering the end of down sprue to be open to atmosphere and an acceleration due to gravity of 10⁴mm/s², the area of the down sprue in mm² at its end (avoiding aspiration effect) should be

(a) 650                                   (b) 350

(c) 290.7                               (d) 190.0