Final answer:
Active volcanoes are predominantly found along tectonic plate boundaries at mid-ocean ridges and above mantle "hot spots" like the Hawaiian hot spot, and are distributed in both the oceans and on the continents.
Step-by-step explanation:
The majority of active volcanoes on Earth are located along the tectonic plate boundaries, primarily under the ocean in what are called the mid-ocean ridges. Additionally, other volcanic activity occurs above mantle "hot spots", like the one under the island of Hawaii, which has created a chain of volcanic islands. Subduction zones, where one tectonic plate slides under another, also tend to have a high concentration of volcanoes, such as those found in the "Pacific Ring of Fire," a path along the Pacific Ocean characterized by active and dormant volcanic sites. While there are active volcanoes on landmasses, such as Mount Erebus in Antarctica, the majority are associated with oceanic processes. Thus, the correct answer to the student's question is: c) In both the oceans and on the continents.