Which pair has an incorrect discontinuity and boundary?

Correct answer: Moho outer and inner core

Direct answer: Option D is the incorrect pair. A discontinuity is a boundary inside Earth where the properties or behaviour of seismic waves change because the material changes. The Moho, or Mohorovičić discontinuity, separates the crust from the mantle, so Option A is correct. The Gutenberg discontinuity separates the mantle from the outer core, so Option B is correct. The Lehmann discontinuity is commonly used for the boundary between the outer core and the inner core, so Option C is correct. Option D is wrong because the Moho is not the boundary between the outer and inner cores; it is near the top of Earth, between crust and mantle. The outer and inner core are separated by the Lehmann discontinuity. Thus the question asks for the wrong pair, and D is the answer. Memory chain from outside inward: Moho = crust–mantle, Gutenberg = mantle–outer core, Lehmann = outer–inner core.