Answer:

The correct answer is option D, Limestone.

Explanation:

Definition of Minerals:
Minerals are naturally occurring inorganic substances that are solid and have a definite chemical composition. They are formed through geological processes and are found in the Earth's crust.

Metallic Minerals:
Metallic minerals are minerals that contain metals in their chemical composition. These minerals have a shiny appearance and are good conductors of heat and electricity. They can be further categorized into two types:

1. Ferrous Minerals: These minerals contain iron and include minerals like iron ore, manganese, and chromite.
2. Non-Ferrous Minerals: These minerals do not contain iron and include minerals like gold, silver, copper, lead, and zinc.

Non-Metallic Minerals:
Non-metallic minerals are minerals that do not contain metals in their chemical composition. They have a non-metallic luster and are poor conductors of heat and electricity. They can be further categorized into two types:

1. Organic Minerals: These minerals are formed from the remains of once-living organisms. Examples include coal and petroleum.
2. Inorganic Minerals: These minerals are formed through geological processes and do not contain any organic matter. Examples include limestone, gypsum, potash, and sulfur.

Explanation of Options:
a) Bauxite: Bauxite is a metallic mineral that is the primary ore of aluminum. It is formed through the weathering of aluminum-rich rocks and is mainly found in tropical and subtropical areas.

b) Gold: Gold is a metallic mineral that is highly valued for its rarity and beauty. It is a soft, yellow metal that is often used in jewelry and as a store of value.

c) Iron Ore: Iron ore is a metallic mineral that contains iron in its chemical composition. It is one of the most important minerals used in the production of steel.

d) Limestone: Limestone is a non-metallic mineral that is composed mainly of calcium carbonate. It is formed through the accumulation of the remains of marine organisms such as coral and shells. Limestone is commonly used as a building material and in the production of cement.

Conclusion:
Among the given options, limestone is the only non-metallic mineral. It is important to understand the distinction between metallic and non-metallic minerals as it helps in studying their properties, uses, and economic significance.