D-The asthenosphere and outer core would solidify.
Explanation:
The athenosphere is a region of the earth mantle below the lithosphere.
If the Sun didn’t retain the heat formed during its formation then it will have an adverse effect on other parts such as the core and mantle.The inner core wouldn’t liquefy but solidify. The asthenosphere and outer core would also solidify.
The Seismic waves wont be able to move the crust and the Earth’s magnetic field wouldn’t disappear but would be more pronounced.