Which term names the cone-shaped volcanic mountains under the earth? a. seamounts b. sand dunes c. trenches d. hot spots

The answer is A. seamounts.

Seamounts are the mountains which are situated underwater. They are mountains with steep sides, rising hundreds or thousands of feet from the seafloor. Actually seamounts are the highest mountain on Earth. They are generally extinct volcanoes. They created huge lava when they were active that sometimes break the ocean surface.