The correct response is:
All plates of Earth's crust move, not just the landmasses.
The Plate Tectonic Theory encompasses a broader understanding of how the Earth's lithosphere is divided into plates that float on the semi-fluid asthenosphere beneath them. This theory explains not only the movement of continents but also the dynamics of oceanic plates and the interactions between them, such as subduction and rifting, which were not adequately addressed by the earlier Continental Drift Theory.