orthogonal cutting process and Merchant’s shear angle relationship

Question

In an orthogonal cutting process rate angle of the tool is 20⁰ and friction angle is 25.5⁰. Using Merchant’s shear angle relationship the value of shear angle will be

(a) 39.5⁰                      (b) 42.25⁰        (c) 47.75⁰                    (d) 50.5⁰