Which statement about lithosphere is most correct?

Correct answer: It is the rigid outer part including crust and part of upper mantle

The direct answer is B: the lithosphere is the rigid outer part of Earth, made of the crust and the uppermost part of the mantle. It is useful to distinguish layers by both composition and physical behaviour. The lithosphere is strong and relatively rigid, and it is broken into tectonic plates that move slowly over the softer asthenosphere below. Option A is wrong because the liquid outer core lies deep inside Earth and is not the lithosphere. Option B is correct because it includes the crust and the rigid upper mantle. Option C is wrong because atmospheric gases form the atmosphere, not the lithosphere. Option D is wrong because the lithosphere is outside the core, not below the inner core. The answer should not say it is only the crust: the upper mantle portion is also included. Memory cue: “lithosphere = rigid plates.”