Stainless steel does not rust because

Question

$\begin{array}{1 1}(a)\;\text{Chromium and nickel combine with iron}\\(b)\;\text{Nickel present in it, does not rust}\\(c)\;\text{Chromium forms an oxide layer and protects iron from rusting}\\(d)\;\text{Chromium present in it, does not rust}\end{array}$