Answer:d
Explanation:
Earth is made up of the following layers
The solid inner core is like a slid ball with an approx radius of 1220 km. High Pressure inside the Solid core stabilizes the solid inside the core while there is slightly lower pressure outside the core which allows the iron to melt.
The iron silicate inside the core is majorly solid but traces of it can be in a melted form that can be found in the asthenosphere.