Which sequence correctly represents the major layers of the Earth from the surface toward the centre?

Correct answer: Crust, mantle, outer core, inner core

The correct answer is B: crust, mantle, outer core, and inner core. To understand the order, imagine moving downward from Earth’s surface. First we meet the crust, the thin, solid rocky outer shell. Below it is the mantle, a much thicker layer of hot rock. Deeper still is the core, which has a liquid outer core and a solid inner core. Thus the order from outside toward the centre is crust → mantle → outer core → inner core. A is wrong because it places the mantle before the crust. C is wrong because it puts the outer core above the mantle. D gives the layers in the reverse direction, from the centre outward. Memory cue: “Crust, Mantle, Outer core, Inner core”—the first letters form CMOI.