The correct answer is Option A.
It was historically used as an ore of aluminium and later in the electrolytic processing of the aluminium-rich oxide ore bauxite (itself a combination of aluminium oxide minerals such as gibbsite, boehmite and diaspore).

The correct answer is Option B.

Calamine is an ore of zinc. It is zinc carbonate ZnCO3.

The correct answer is Option A.
Malachite is a green copper carbonate hydroxide mineral with formula Cu2(CO3)(OH)2. It is of minor importance today as an ore of copper because it is usually found in small quantities and can be sold for higher prices for other types of use.

Correct Answer is option D
 
(Acidic Impurity) SiO₂ + (Basic Flux) CaO →(Slag) CaSiO₃

In this process sulphide ores are converted into oxide ores
2ZnS + 3O₂ →2ZnO + 2SO²

The correct answer is Option C.

A native metal is any metal that is found in its metallic form, either pure or as an alloy, in nature.
For example, gold.
Gold exists as it is less reactive and does not form any kind of alloys in its natural state.

The correct answer is option D
Aluminium
Bauxite is the most important ore of aluminium which contains only 30 –54% alumina, Al₂ O₃ ; the rest is a mixture of silica, various iron oxides, and titanium dioxide along with trace amounts of zinc, phosphorus, nickel, vanadium etc.
 

The correct answer is Option D.
Dolomite : CaMg(CO3)2
It contains both calcium and magnesium.

The answer is option B
Pyrolusite is MnO₂ . Thus, it is an oxide ore. It is a black, amorphous appearing mineral, often with a granular, fibrous or columnar structure, sometimes forming reniform crusts.