The correct answer to this open question is the following.
A Batholith is a magma chamber that is solidified.
When magma cools in the depth of the earth's crust and it is not exposed to the surface, forms a giant mass of igneous rock called Batholith. It is formed of coarse-grained granite, and its formation happens when magma rises into the earth's crust, as we stated above. These structures are huge and can extend up to forty square miles.
