The correct answer is (a) Magnesite.
Magnesite is a magnesium carbonate mineral with the chemical formula MgCO3. It is a white, gray, or brown mineral that is found in metamorphic and sedimentary rocks. Magnesite is used in a variety of industries, including the chemical, metallurgical, and refractory industries.
Graphite is a form of carbon that is found in metamorphic and igneous rocks. It is a black, gray, or brown mineral that is used in a variety of industries, including the electrical, metallurgical, and lubricant industries.
Gypsum is a calcium sulfate mineral with the chemical formula CaSO4·2H2O. It is a white, colorless, or gray mineral that is found in sedimentary rocks. Gypsum is used in a variety of industries, including the construction, agricultural, and pharmaceutical industries.
Dolomite is a calcium magnesium carbonate mineral with the chemical formula CaMg(CO3)2. It is a white, gray, or brown mineral that is found in sedimentary rocks. Dolomite is used in a variety of industries, including the construction, metallurgical, and refractory industries.