What do we call magma that is released to the surface of the Earth?

When magma reaches the surface of the Earth, it is called lava. This transformation occurs when molten rock, which is found beneath the Earth's surface (known as magma), erupts through volcanic activity or other geological processes. Once exposed to the cooler temperatures at the surface, the lava begins to solidify and can form various types of volcanic rock.

The distinction between magma and lava is significant in geology. Magma is the molten rock that is still underground, while lava is specifically the term used once it exits the Earth's crust. This process is crucial for understanding volcanic activity and the formation of different geological structures.

Other terms in the options, like "rock" and "granite," do not accurately describe magma once it has been released. "Rock" is a general term for solid aggregates of minerals, and "granite" is a specific type of rock that forms from slowly cooled magma deep within the Earth. Therefore, lava is the correct term for magma that is exposed on the surface.