What are the three main parts of the geosphere?

a. atmosphere, crust, core

b. lithosphere, mantle, core

c. crust, mantle, core

d. asthenosphere, lithosphere, atmosphere

I think the correct answer from the choices listed above is option C. The three main parts of the geosphere are the crust, the mantle and the core. Geosphere is sometimes referred as to the term lithosphere. It is the part of the Earth that includes the Earth's interior.