Viscosity is defined as the external resistance offered by a fluid to change its shape or relative motion of its parts.
(a) Yes
(b) It is internal resisting force
(c) It is not offered but exerted on the fluids
(d) None of the listed
The question was asked during thesis preparation.
This key question is from the Viscosity section in chapter Rolling Contact Bearings, Spur Gears and Helical Gears of Machine Design