ANS:C - flakes

In grey cast iron, carbon exists in the form of flakes or lamellar structures. These flakes are essentially graphite particles dispersed throughout the iron matrix. The presence of these graphite flakes gives grey cast iron its characteristic gray color. The flakes provide lubrication and act as crack initiators, influencing the material's mechanical properties. Due to the presence of graphite flakes, grey cast iron has good machinability but relatively low strength and ductility compared to other types of cast iron.