Which pair incorrectly matches a layer and state?

Correct answer: Outer core solid

The direct answer is D: outer core solid. The question asks for the incorrectly matched layer and state. Earth’s crust is solid rock, so option C is a correct match. The inner core is also treated as solid because the enormous pressure keeps the iron-rich material in a solid state, so option B is correct. The outer core is mainly molten iron and nickel, so it is liquid; therefore option A is also correct. Option D says that the outer core is solid, which is the incorrect pair. Step by step: identify the layer, recall its physical state, and compare it with the option. The outer core lies below the mantle and surrounds the inner core. Unlike the inner core, it is liquid. This conclusion is strongly supported by earthquake waves: S waves cannot pass through liquids, while P waves can pass through them, although their speed and path change. Option A is correct, not the answer, because the outer core is liquid. Option B is correct because pressure makes the inner core solid. Option C is correct because the crust is the solid outer rocky layer. Option D is wrong because it gives the wrong state for the outer core. Common mistake: do not interchange the outer and inner core. The outer core is liquid; the inner core is solid.