The correct answer is (d). Dolomite is an example of an igneous rock, while quartzite, marble, and gneiss are all examples of metamorphic rocks.
Igneous rocks are formed when magma or lava cools and solidifies. Metamorphic rocks are formed when existing rocks are subjected to heat and pressure, which causes them to change their composition and texture. Quartzite is a metamorphic rock that is formed when sandstone is subjected to heat and pressure. Marble is a metamorphic rock that is formed when limestone is subjected to heat and pressure. Gneiss is a metamorphic rock that is formed when granite is subjected to heat and pressure.
Dolomite is a sedimentary rock that is formed when limestone is dissolved and then re-precipitated. It is composed of calcium magnesium carbonate, which is a mineral that is also found in limestone. Dolomite is a relatively soft rock that is easily scratched or broken. It is often used as a building material or as a decorative stone.