Extrusion is not a casting process.

Casting process :In casting process, the molten metal is poured into a cavity or mould of the desired shape and allowing it to solidify.The solidified object is called casting and the process is called casting process.

Extrusion process :It is the process of enclosing the billet or slug of metal in a closed cavity and then pushing it to flow from only one die opening so that the metal will take the shape of the opening.

Hence, the correct option is (B).