A disk clutch is required to transmit \(5 \mathrm{~kW}\) at \(2000 \mathrm{rpm}\). The disk has a friction lining with coeffient of friction equal to 0.25 . Bore radius of friction lining is equal to \(25 \mathrm{~mm}\). Assume uniform contact pressure of \(1 \mathrm{MPa}\). The value of outside of the friction lining is

(a) \(39.4 \mathrm{~mm}\)

(b) \(49.5 \mathrm{~mm}\)

(c) \(97.9 \mathrm{~mm}\)

(d) \(142.9 \mathrm{~mm}\).