Among the following, the correct statement is 

Let us review the given statements.

a) It is not true because a body which is having constant velocity will maintain both magnitude and direction as constant so there is no chance for varying speed.

b) It is true because a body moving with constant speed can produce no displacement while moving in a circular path with constant speed its displacement will become zero after completing every revolution.

c) It is not true because while moving with constant speed in a circular path body will gain acceleration.

d) It is true because while moving in a curved path or circular path a body can produce

varying velocity from one point to another point