Answer: c. hot plumes of mantle material that rise up through cooler, denser surrounding rock
Step-by-step explanation:
A hot spot is simply refered to an area that is very hot below the Earth. Here, the magma is typically hotter than the magna of its surrounding. It should be noted in this case that the magma plume then results in volcanic activity.
According to the model proposed by geophysicist J. Tuzo Wilson, hot spots are caused by hot plumes of mantle material that rise up through cooler, denser surrounding rock. Therefore, the correct answer is C.