Which Statement Regarding the Formation of an Alloy Is Correct

Multiple Choice

Which statement regarding the formation of an alloy is correct?

A) Carbon forms an interstitial alloy with iron because their atomic radii are about the same.
B) Carbon forms a substitutional alloy with iron because their atomic radii are about the same.
C) Carbon forms an interstitial alloy with iron because carbon has a much smaller atomic radius.
D) Carbon forms a substitutional alloy with iron because carbon has a much smaller atomic radius.
E) Carbon forms an interstitial alloy with iron because carbon has a much larger atomic radius.