Which statement correctly explains the formation of Earth's core?

Correct answer: Heavy metals sank inward in molten Earth

Direct answer: A, heavy metals sank inward in the molten Earth. Early Earth was heated by collisions, compression and radioactive processes, so much of it became molten or partly molten. In this state, dense materials such as iron moved downward under gravity, while lighter silicate materials moved upward. This separation is called differentiation and produced layers: a metallic core, a rocky mantle and a crust. Option A gives this exact process. Option B is wrong because light gases do not freeze to create the core; gases generally escaped or formed part of the atmosphere. Option C is impossible because sea water cannot transform into the metallic core in this way. Option D is not the accepted explanation of core formation. Memory cue: differentiation means dense down, light up.