Copper and silver are also found in the form of sulphide and oxide ores. Metals found in the middle of reactivity series, such as Zn, Fe, Pb, etc. are usually found in the form of oxides, sulphides or carbonates.

Iron ore is a mineral substance which, when heated in the presence of a reductant, yields metallic iron (Fe). It is one of the most abundant rock-forming elements found in the Earth's crust. Iron ore is primarily used in the production of iron and steel, which are essential materials for various industries including construction, automotive, and manufacturing.

Iron ore is typically found in the form of various minerals, including oxides, carbonates, and sulphides. These different forms of iron ore have distinct chemical compositions and physical properties. The correct answer to the question is option 'D', which states that iron ore is found in all of these forms.

Let's explore each form of iron ore in detail:

1. Oxides:
- Iron oxide minerals are the most common form of iron ore.
- The two main types of iron oxide minerals are hematite (Fe2O3) and magnetite (Fe3O4).
- Hematite is the most abundant iron ore mineral and is typically reddish-brown in color. It has a high iron content and is often used in the production of iron and steel.
- Magnetite is a magnetic iron ore with a black metallic luster. It has a slightly lower iron content compared to hematite but is still an important source of iron.

2. Carbonates:
- Iron carbonate minerals are less common than iron oxides but can still be found in significant quantities.
- The main iron carbonate mineral is siderite (FeCO3).
- Siderite is usually brownish-yellow or gray in color and has a lower iron content compared to hematite and magnetite.

3. Sulphides:
- Iron sulphide minerals are less common and usually found in smaller quantities compared to iron oxides and carbonates.
- The main iron sulphide mineral is pyrite (FeS2), also known as "fool's gold".
- Pyrite is a brassy yellow mineral that is often mistaken for gold due to its metallic luster. However, it does not contain significant amounts of iron and is not used as an iron ore.

In conclusion, iron ore is commonly found in the form of oxides (hematite and magnetite), carbonates (siderite), and sulphides (pyrite). These different forms of iron ore have distinct properties and are used in various industries for the production of iron and steel.