Option 1 -> Bauxite is an aluminum ore, classified as a non-ferrous mineral.
Option 2 -> Iron ore contains iron and is the primary example of a ferrous mineral.
Option 3 -> Limestone is a sedimentary rock composed of calcium carbonate, not a ferrous mineral.
Option 4 -> Copper is a non-ferrous metal/mineral.
Hence, Option 2 (Iron ore) -> Ferrous minerals are those that contain iron, derived from the Latin word "ferrum" meaning iron. Iron ore is the most important ferrous mineral used in steel production and various industries -> correct