Which parts are generally included in the lithosphere?

Correct answer: Crust and rigid upper mantle

The direct answer is A: the crust and the rigid part of the upper mantle. The lithosphere is Earth’s hard, outer layer. It includes the crust, which is the thin rocky surface on which continents and ocean floors rest, and the uppermost mantle that is sufficiently rigid to behave as solid rock. The lithosphere is broken into tectonic plates that move slowly over the softer asthenosphere below. Option A is correct because it gives both main components. Option B, only the outer core, is wrong because the outer core lies much deeper and is liquid metal, not part of the lithosphere. Option C, only oceans, is wrong because oceans are water; oceanic crust is part of the lithosphere, but the whole lithosphere is not only oceans. Option D, only atmosphere, is wrong because the atmosphere is the gaseous envelope around Earth. Reasoning: crust + rigid uppermost mantle = lithosphere. Memory cue: lithosphere means the hard rocky shell, not the liquid core, air or water alone.