betu,

u say that on an incline, weight of the sphere would provide the torque.but what  i think is that without friction rolling would not be possible.the weight would only help in sliding down and not in rotating.as it is the weight passes through centre of mass.so its torque about centre of mass would be zero.

so i say both (A) & (B) are right.but the answer is only (B).so i stand wrong somewhere.

if possible could u plzzz check another set of m c q of mine named as 'rotation based questions'?i have common conceptual problem in the 3 mcq.

i would surely rate u