Final answer:
The magnetic attraction between the Earth's liquid outer core and the lithosphere is not thought to contribute to the motion of the Earth's tectonic plates.
Step-by-step explanation:
While all the other options mentioned contribute to the motion of the Earth's tectonic plates, the magnetic attraction between the Earth's liquid outer core and the lithosphere does not play a role in plate motion. The option that is not thought to contribute to the motion of the Earth's tectonic plates is 3. magnetic attraction between the Earth's liquid outer core and the lithosphere.
The Earth's magnetic field does result from movements within the liquid outer core, what drives the tectonic plates' movement are more substantial physical forces and processes The motion of tectonic plates is primarily driven by convection in the Earth's mantle, the downward slope of the lithosphere between mid-ocean ridges and oceanic trenches, the wedging of ascending magma between diverging plates, and the increasing density of the plate with increasing distance from the divergent plate boundary.