Concept:Igneous rocks are grouped by where the cooling of magma or lava takes place.
Explanation:Magma that cools and solidifies while still trapped within the Earth's crust forms intrusive igneous rocks known as plutonic rocks.
Because the surrounding crust insulates the magma, it cools very slowly, allowing large crystals to grow.
In contrast, volcanic rocks, also called extrusive igneous rocks, form when lava reaches the Earth's surface and cools rapidly.
Rapid surface cooling produces fine-grained textures, whereas slow underground cooling produces coarse-grained textures.
Stratified is a term used for sedimentary rocks that are arranged in distinct layers, so it does not apply to igneous rocks in this context.
Quartzite is a metamorphic rock that forms when sandstone is altered by heat and pressure, not from magma.
Therefore, the correct term for igneous rocks formed within the crust is plutonic.
Answer:A. plutonic