Four copper-based alloys are listed below. Based on lattice distortion considerations alone, which alloy is expected to be the most ductile at room temperature?
Alloy I: Cu + 5 at.% Zn (atomic radius Zn ≈ atomic radius Cu)
Alloy II: Cu + 2 at.% Al (atomic radius Al slightly smaller than Cu)
Alloy III: Cu + 0.8 at.% C (atomic radius C ≪ Cu)
Alloy IV: Pure Cu
a) Alloy II
b) Alloy IV
c) Alloy I
d) Alloy III