ANS:B - impact strength

Grey cast iron, compared to steel, has higher machinability. Grey cast iron is a type of cast iron characterized by its graphite flakes distributed throughout the metal matrix. This graphite provides lubrication during machining, which makes grey cast iron easier to machine compared to steel. The graphite also helps to dampen vibrations during cutting, reducing the risk of chatter and tool wear. Steel, on the other hand, generally requires more energy and specialized tooling for machining due to its higher strength and hardness compared to grey cast iron. Therefore, the correct answer is machinability.