Answer:
b. Extrusive igneous rocks
Step-by-step explanation:
Generally, igneous rocks are rocks that forms from the solidification of a semi molten liquid called magma. Large percentage of the earth is covered by igneous rocks and most of the earth oceanic ridges is made from igneous rocks.
Magma's that are solidified below the earth surface are usually called the instrusive igneous rocks for example granite . Magma's that creeps to the surface of the earth are called Lava and the kind of igneous rocks formed here are called Extrusive igneous rocks because they solidified on the surface of the earth. Example of extrusive igneous rocks is the basalt