Final answer:
Austenitizing is a heat treatment process performed on iron-based alloys to change their crystal structure to austenite. The correct answer is c) Iron, as aluminum, copper, and lead cannot undergo this specific treatment, which is mainly used for steel.
Step-by-step explanation:
The process of austenitizing is a heat treatment that is performed on iron-based alloys. This treatment involves heating the metal to a temperature at which its crystal structure changes to form austenite, which is a face-centered cubic (FCC) structure. Among the options provided, c) Iron is the metal on which austenitizing can be performed. This process is primarily associated with the treatment of steel, which is an alloy of iron and carbon, and some other alloying elements.
For clarification, aluminum, copper, and lead cannot undergo austenitizing as this process is specific to iron-based alloys. The mention of d-block metals and their isolation processes such as smelting and refining relate to the production of metals in their pure form, while austenitizing is part of the heat treatment for modifying the properties of metals after they have been isolated and refined.