Final answer:
The inner core of the Earth is composed of solid nickel and iron.
Step-by-step explanation:
The student asked which composition makes up the inner core of the Earth. The correct answer is a) Solid nickel and iron. The inner core is the deepest layer of the Earth and despite the high temperatures, it remains solid due to the immense pressure from the layers above. Surrounding the solid inner core is the liquid outer core, which is responsible for the Earth's magnetic field. Above the core is the mantle, a massive layer of solid rock that can flow very slowly, followed by the crust, which is the outermost layer of the Earth.