A factory has three belt conveyors fitted in its loading station. Conveyors A and B operating simultaneously lift all the goods in the same time during which the goods can be lifted by the conveyor C operating alone. Conveyor B lifts all the goods five hours faster than the conveyor C. The durations of time required to lift all the goods, individually by the conveyors A, B and C are

(a) 17, 12, 8 hrs.
(b) 15, 10, 6 hrs.
(c) 16, 11, 7 hrs.
(d) 14, 9, 5 hrs.