Two shafts will have equal strength, if
(a) diameter of both the shafts is same
(b) angle of twist of both the shafts is same
(c) material of both the shafts is same
(d) twisting moment of both the shafts is same
(a) diameter of both the shafts is same
(b) angle of twist of both the shafts is same
(c) material of both the shafts is same
(d) twisting moment of both the shafts is same