Which of the following are the three main types of rocks?

The three main types of rocks are igneous, sedimentary, and metamorphic rocks. Igneous rocks form from the solidification of molten material, either magma beneath the earth's surface (intrusive) or lava that erupts onto the surface (extrusive). Sedimentary rocks are created from the accumulation and compaction of sediment, which can include fragments of other rocks, minerals, and organic materials. Metamorphic rocks result from the alteration of existing rocks due to changes in temperature, pressure, or chemically active fluids, without the rock melting.

This classification into igneous, sedimentary, and metamorphic encompasses all the variations of rocks found in nature, allowing geologists to understand their origins and the processes that formed them. The other choices list specific types of rocks or categories that fall within these broader classifications but do not encapsulate the full scope of the three main rock types.