Answer:
The correct answer is - a. To keep the Earth's surface area constant, the amount of seafloor spreading must equal the amount of subduction.
Explanation:
Subduction is the process of the movement in the plate tectonics of the edge of one crustal plate or oceanic lithosphere descending below the edge of another or earth's mantle. Seafloor spreading is the splitting of the ridges of the earth's surface or slabs due to volcanic activity.
On the basis above we can say that the amount of subduction and the amount of seafloor spreading are equal then the Earth's surface area will remain constant.
