Then change gear to be used is

Question

Centre lathe is to be used to cut inch thread of 4 threads per inch. Lead screw of lathe has 3 mm pitch. Then change gear to be used is                                             

(a) $\frac{1}{12}$      (b)$\frac{127}{60}$           (c)$\frac{30}{127}$​​​​​​​              (d) $\frac{20}{80}$​​​​​​​