Igneous rocks formed within the crust are called

Igneous rocks are rocks that are formed from the solidification of molten material, known as magma or lava. This can happen both below the Earth's surface and on the surface.

In this question, we are specifically looking at igneous rocks that are formed within the crust, which is the outermost layer of the Earth. These rocks are called "plutonic" rocks.

Plutonic rocks are formed when magma cools and solidifies slowly beneath the Earth's surface. This slow cooling allows the crystals within the rock to grow larger, resulting in a coarse-grained texture. Examples of plutonic rocks include granite and diorite.

The other options in the question are not correct for igneous rocks formed within the crust.

- Quartzite is a metamorphic rock that is formed from the recrystallization of quartz grains. It is not an igneous rock.

- Volcanic rocks, as the name suggests, are formed from lava that erupts onto the Earth's surface. They have a fine-grained texture due to rapid cooling. Examples of volcanic rocks include basalt and pumice.

- Stratified rocks, also known as sedimentary rocks, are formed from the accumulation and compaction of sediments over time. They are not igneous rocks.

Therefore, the correct answer to this question is option C: plutonic.