Final answer:
The function of the geosphere mentioned in the options is the composition of Earth's crust.
Step-by-step explanation:
The geosphere has several functions, but the specific function mentioned in the options is d) Composition of Earth's crust. The geosphere, which includes the lithosphere (the solid outer layer of Earth) and the asthenosphere (the partially molten layer beneath the lithosphere), is responsible for forming and maintaining the Earth's crust. The geosphere is involved in processes such as plate tectonics, volcanic activity, and the formation of rocks and minerals. For example, through plate tectonics, the geosphere contributes to the creation of continental landmasses and ocean basins.