During the production of iron and steel. — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

Step 1: Oxygen is the most abundant element in the Earth's crust, constituting approximately 46.6% of its mass. Step 2: Silicon is the second most abundant element (~27.7%), and aluminium is the third (~8.1%). Step 3: Therefore, oxygen is the most abundant element in the earth crust, which corresponds to option (d).