Concept:Igneous rocks that form when magma cools and solidifies inside the Earth are called plutonic rocks.
Explanation:Magma is the hot, molten rock that exists beneath the Earth's crust.
When magma solidifies while still within the crust and does not reach the surface, the resulting rock is classed as an intrusive or plutonic rock.
Because the surrounding rocks insulate the magma, cooling is slow, which allows large crystals to grow.
This coarse texture is a key feature of plutonic rocks.
Extrusive rocks form from lava that cools quickly on the Earth's surface.
Sedimentary rocks are produced by the compaction and cementation of sediments, not by magma.
Metamorphic rocks are created when existing rocks are changed by heat and pressure.
Only plutonic rocks match the description of magma solidifying within the Earth's crust.
Answer:C. plutonic rocks