Correct option is C
Chalk powder is commonly used for marking on casting surfaces because castings have rough, dark, and porous surfaces, making it difficult to mark using conventional methods.
· Chalk powder provides a visible white contrast on the dark surface of cast metal, ensuring clear marking.
· It is applied in powder or liquid form to create a temporary, easily removable marking for further machining or inspection.
· Used in foundries and metalworking industries, chalk markings help in identifying machining points, part numbers, and inspection areas.
