Final answer:
The most common magma type that erupts from volcanoes is basaltic magma. It has a low viscosity which facilitates its journey to the Earth's surface, leading to the formation of volcanic (extrusive) rocks with small grain crystals.
Step-by-step explanation:
Basaltic magma:
The magma type that most commonly rises to the Earth's surface and erupts from a volcano is D. basaltic magma.Basaltic magma is typically involved in the formation of oceanic crust and is also responsible for lava flows both on land and underwater. It has a relatively low viscosity compared to other magma types, which allows it to reach the Earth's surface more easily.
Granitic magma, which is high in silica, cools and crystallizes more slowly, typically forming large crystals and resulting in intrusive igneous rocks such as granite. Potassium-rich magmas and plutonic magmas (related to plutonic rocks) generally do not erupt because they are too viscous. Therefore, it's primarily basaltic magma that forms extrusive or volcanic igneous rocks, characterized by small crystal grains due to the rapid cooling of lava upon contact with the atmosphere or ocean water.