Which statement best describes an igneous intrusion?
a. magma explodes to the surface and forms a smooth outer layer of rock.
b. igneous intrusion for when ice crystals splash into lava.
c. magma is injected into surrounding rock forming an igneous intrusive.
d. magma is exported to an open area and forms iron.

The right option is C. Magma is injected into surrounding rock forming an igneous intrusive.

An igneous intrusion is a formation in which magma rises up below the surface of the Earth and intrude into other rocks located above it forming an igneous intrusive and leaving them in a dome shape. The magma cools and solidifies before it gets to the surface and it is later exposed as the broken sedimentary rock on top of it gradually wears away. The two types of igneous intrusion are; intrusive and extrusive rocks.