Steel is an alloy of _____.

Options

A. Iron
B. aluminium
C. cobalt
D. all of these

Explanation

**Step-by-Step Solution:**

1. **Understanding the Definition of Alloy**: An alloy is a mixture of two or more elements, where at least one of the elements is a metal. Alloys are created to enhance certain properties of the base metal.

2. **Identifying the Components of Steel**: Steel is primarily composed of iron. It is important to note that it also contains a small percentage of carbon, which contributes to its hardness.

3. **Percentage of Carbon in Steel**: In steel, carbon is typically present in a small amount, usually around 1.7%. This small addition of carbon significantly alters the properties of iron, making it stronger and more durable.

4. **Conclusion**: Based on the information gathered, we can conclude that steel is an alloy of iron and carbon. However, the primary component is iron.

5. **Final Answer**: Therefore, the answer to the question "Steel is an alloy of _____" is "iron".

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