(b) The velocity vector of a particle at a point is always along the tangent to the path of the particle at that point.
(c) The acceleration vector of a particle in uniform circular motion averaged over one cycle is a null vector.
(b) True, the velocity is always tangential, if the motion is uniform or not.
(c) True, When particle returns to its original position after completing one cycle, its displacement is zero. Hence, average velocity and acceleration over one complete cycle is zero, which is null vector.