Hawaii
a: was created by a hotspot
b: is the result of years of seafloor spreading
c: was formed from mudslides caused by earthquakes
d: is an example of the destructive power of volcanoes

A. was created by a hotspot.

Hawaiian islands were formed by volcanic activity.

The correct answer is option A, that is, was created by a hotspot.  

The outer crust of the Earth is produced by an array of tectonic plates, which move over the planet's surface. In the regions, where the plates associate, the formation of volcanoes takes place sometimes. Volcanoes can also get produced in the center of the plate, where the elevation of magma takes place upwardly, till it gets erupt on the seafloor, this is known as a hot spot.  

The formation of Hawaiian Islands took place by such a hot spot in the middle of the Pacific plate. While the plate is moving, the hot spot itself is fixed. Thus, as the movement of the plates takes place over the hot spot, the string of islands, which forms the Hawaiian Island chain was formed.