Which one of the following elements is alloyed with iron to produce steel which can resist high temperatures and also have high hardness and abrasion resistance?

Chromium is the correct answer because it is a key alloying element used to enhance the properties of steel. When added to iron, chromium forms a hard and stable oxide layer on the surface. This significantly improves the steels hardness and resistance to abrasion. Most importantly, chromium provides excellent oxidation resistance at high temperatures, allowing the steel to maintain its structural integrity and resist corrosion even in extreme heat conditions. While other elements like tungsten also provide hardness, chromium is the primary element used for the specific combination of high temperature resistance, hardness, and wear resistance.