Answer: Slab Pull
Explanation:
Whilst I was unable to find the options for your question I believe the answer to be the Slab Pull.
Slab Pull refers to the force exerted by an oceanic plate sinking into the mantle.
The Slab Pull happens because the oceanic plate is colder and denser than the hotter mantle and this difference causes the plate sink further and as it does so it pulls the rest of the plate along with it in a process called Subduction. This is why the question called it a Subducting Plate.
I have attached a diagram showing the process.
