Given that cutting speed =9 m/min, the return time to cutting time ratio is = 1:2 the feed rate = 0.3 mm/stroke , the clearanceat each of cut = 25 mm and that the plate Is fixed 700 mm side along the direction of tool travel, the time required for finishing one flat surface of a plate of size 700 $$\times$$ 300 mm in a shaper, will be

A

10 min

B

12.5 min

C

15 min

D

20 min