Personally I would go for answer 2, but I am not completely sure
I would say that plate tectonics shows what the origin of volcanic activity, earthquakes and mountains comes from their collision or subduction. Where two plates collide mountains can be formed (uplift), where subduction occurs then volcanic activity like in the circum-pacific belt occurs and where stresses build up in subduction or transform fault (like the San Andreas Fault) and are suddenly released, earthquakes are the result. Subduction is where the oceanic plate gets pushed under the continental plate.
The first thing that came to my mind when i read that phrase was that whatever this "script" is, it must be a pretty awesome piece of work.
Answer: Tectonic plates move because..
Explanation: The heat from radioactive processes within the planet's interior causes the plates to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift. I hope this helped.
