Which of the following layers is involved in the movement of tectonic plates?

The lithosphere is the outermost layer of the Earth and is composed of the crust and the uppermost portion of the mantle. It is rigid and brittle, forming the tectonic plates that float on the more fluid layers beneath them. The movement of these tectonic plates is primarily driven by the heat and convection currents occurring in the underlying layers, particularly the asthenosphere, which allows the plates to shift.

While the asthenosphere does play a significant role in supporting the movement of the lithospheric plates due to its semi-fluid nature, the actual plates themselves are part of the lithosphere. The inner core and outer core do not participate in the movement of tectonic plates as they are located much deeper within the Earth and serve different functions, like generating the Earth's magnetic field.