What is the formula for finding gear ratio for fractional pitch thread?

A. DR/DN = Leads of screw to be cut X No. Of threads per inch of lead screw

B. DR/DN = TPI on lead screw/ TPI to cut

C. DR/DN = Lead of head screw/ Lead of work

D. DR/DN = Lead of work/ No. Of threads per inch

Correct Answer: DR/DN = Leads of screw to be cut X No. Of threads per inch of lead screw