Which of these components is commonly found in steel, an example of an alloy?

Steel is primarily made up of iron, but it also contains carbon, which is a crucial component that enhances its properties. The presence of carbon in the iron structure increases hardness and tensile strength, making the steel more durable and resistant to deformation under stress. This modification is a key aspect of what makes steel an alloy, as its properties are significantly altered from pure iron through the addition of carbon.

In contrast, metals such as silver, copper, and lead are not typical components of steel. While copper can be used in certain steel alloys for specific properties such as corrosion resistance, it is not a fundamental element of standard steel. Silver is generally used in different applications, particularly in electronics or jewelry due to its conductivity and aesthetic appeal, and lead is not included in steel due to its toxicity and weight, which do not align with the desired properties of steel. Therefore, carbon stands out as the correct answer because it is integral to the formation of steel and directly influences its performance characteristics.