how to calculate internal rate of return of an asset

The Valentine Company has decided to buy a machine costing $37,720. Estimated cash savings from using the new machine amount to $8,000 per year. The machine will have no salvage value at the end of its useful life of thirteen years. (Ignore income taxes.)

If Valentine's required rate of return is 12%, the machine's internal rate of return is closest to:

a.15%

b.19%

c.17%

d.13%