Casting is a fabrication process in which a completely molten metal is poured into a mold cavity having the desired shape - upon solidification, the metal assumes the shape of the mold but experiences some shrinkage. A number of different casting techniques are commonly employed, including sand, die, investment, lost-foam, and continuous casting.

• A. Rolling
• B. Casting
• C. Forging
• D. Extrusion

Answer: (B)

The main idea tested here is that casting is the process of pouring molten metal into a mold cavity and letting it solidify to take the mold’s shape, with shrinkage occurring as it cools. Casting covers methods like sand casting, die casting, investment casting, lost-foam, and continuous casting, which all rely on liquid metal filling a mold and then solidifying in that form.

Rolling, forging, and extrusion are metalworking processes that shape metal while it is solid or hot worked, not by filling a mold with molten metal. Rolling reduces thickness or cross-section by passing between rolls; forging shapes metal by compressive deformation between dies; extrusion pushes metal through a die to create a desired cross-section. These differ from casting in that they do not involve pouring liquid metal into a mold to form the final shape.

So the description matches casting—the process of forming a part by pouring molten metal into a mold and allowing it to solidify, with shrinkage during solidification.