Correct option is A
Facing is a lathe operation used to produce a flat surface at the end of a cylindrical workpiece. It ensures that the end surface is perpendicular to the axis and at the correct length. This operation is commonly performed before other machining processes to prepare a reference surface.
Other operations serve different purposes: knurling creates a textured surface, step turning produces different diameters, and chamfering removes sharp edges.
Thus, since the question refers to making the plain ends of a job, facing is the correct operation.
