Why Can't Chromium and Nickel Form a Miscible Solid Solution

Why can't chromium and nickel form a miscible solid solution over the entire composition range?

A) The lever rule says that these two metals can't coexist in an alloy.
B) The two metals crystallize into different cubic structures in their pure forms.
C) The tetrahedral holes in the nickel crystal are not large enough to accommodate the chromium.
D) The octahedral holes in the chromium crystal are not large enough to accommodate the nickel.
E) Chromium atoms can only fit inside tetrahedral holes, which are not present in the structure of pure nickel.