Answer: D. diffusive manufacturing
Process manufacturing involves altering the natural or original form or structure of a material either physically or chemically, to form a new product.
Utilitarian production involves making products that are ethically acceptable.
Assembly process is the arrangement of equipment, machines, and workers before a product is created. It is the sequential arrangement of these machines and equipment in a way that production progresses from one stage to the next stage.
Diffusion manufacturing is specific to the production of steel. It is used to increase the degree of hardness of steel products.