(d) All the statements are correct. Molybdenum alloys have high melting points, excellent strength at elevated temperatures, and good wear resistance. They are used in extrusion dies, rocket nozzles, and structural components in aerospace and space applications. Tantalum is highly corrosion-resistant, especially to acids (like HCl and H2SO4 ) below 150∘C. It is used in chemical processing equipment, medical implants, and electronic components due to this property. Superalloys (nickel-based, cobalt-based, etc.) are designed to retain mechanical strength, oxidation resistance, and thermal stability at high temperatures. Widely used in jet engines, gas turbines, and aerospace applications.