Which type of rock is formed from the cooling and solidification of molten material?

Igneous rock is formed from the cooling and solidification of molten material, which can either be magma or lava. When magma cools slowly beneath the earth's surface, it forms intrusive igneous rocks, such as granite, characterized by their coarse-grained texture. Conversely, when lava erupts onto the surface and cools quickly, it creates extrusive igneous rocks, such as basalt, which tend to be fine-grained due to rapid cooling. This process explains why igneous rock is directly tied to volcanic activity and geothermal processes.

The other types of rock listed—sedimentary and metamorphic—are formed through different processes. Sedimentary rock forms from the accumulation and consolidation of mineral and organic particles, while metamorphic rock arises from the alteration of existing rock types through heat, pressure, and chemically active fluids. Residual rock isn't a widely recognized category in geology and does not accurately define a rock type related to cooling and solidification. Therefore, igneous rock is the correct answer as it directly relates to the formation process from molten material.