Hi there!
The seafloor spreading is when the mantle is rising and breaking the crust causing the seafloor to spread open. Continental Drift is the gradual movement of the continents across the earth's surface through geological time. Induction is the process or action of bringing about or giving rise to something. Subduction the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate.
Thus makes Subduction your answer:)