What is the shearing stress developed ion the cotter?

Question

In a cotter joint, the width of the cotter at the centre is 50mm and its thickness is 12mm. The load acting on the cotter is 60kN. What is the shearing stress developed ion the cotter?

(a) 120 N/mm²                     (b) 100 N/mm²

(c) 75N/mm²                      (d) 50 N/mm²