B (plate tectonics). The others are not directly related to these physical processes while earthquakes are caused by plates shearing across eachother and volcanoes by plates pulling apart--exposing the earth's crust.
plate tectonics! Earthquakes occur when the Earth's tectonic plates bump and slide past each other. Volcanoes are formed when the tectonic plates collide and overlap each other. Volcanic eruptions could also cause earthquakes.
