A project would have a net present value of 7m if the product being produced was sold at the planned selling price of 4.10 per unit, but would have a net present value of -5.1m if the product being produced was sold at 3.2 per unit. The margin of safety in relation to the planned selling price of the product is closest to:

A. 7.7%

B. 17.7%

C. 12.7%

D. 22.7%