The example of completely constrained motion is a
A. Motion of a piston in the cylinder of a steam engine
B. Motion of a square bar in a square hole
C. Motion of a shaft with collars at each end in a circular hole
D. All of the above
Answer: Option D

Option c is successfully constrained motion so the answer is b.
A hoga answer
Because in all of these 3 only 1 kind of motion is possible..