The correct option is D air and saline water
Rust is an iron oxide, usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture. Several forms of rust are distinguishable both visually and by spectroscopy, and form under different circumstances. Rust consists of hydrated iron(III) oxides Fe2O. The reason of rapid rusting in saline water is that the process of rusting involves electrons moving around, and electrons move more easily in salt-water than they do in clean water.