torque carrying capacity of the clutch

Question

A clutch has outer and inner diameters 100mm and 40mm respectively. Assuming a uniform
pressure of 2MPa and coefficient of friction of inner material 0.4, the torque carrying capacity of
the clutch is

(a) 148 Nm                  (b) 196 Nm
(c) 372 Nm                  (d) 490 Nm