a) Real weight
Newton's laws of motion hold good - sometimes. At other times, they appear not to work.
All inertial frames of reference move with constant velocity with respect to all other inertial frames. Therefore, Newton's laws of motion always hold good in these frame of reference.
We know that
If accleration is due to force of gravity, then the expression becomes
As explained above in all inertial frames of references the laws of Newtonian mechanics hold good.
As such weight of a body in an inertial frame is its actual weight.