The correct answer is - D. Top soil is eroded by rain water.
The geosphere is the sphere that contains all the rocky, crustal part of the surface of the Earth and the lesser depths of it. The hydrosphere is the sphere that contains all of the water on the planet.
The soil is part of the geosphere, while the rain water is part of the hydrosphere. When both of these come in touch, thus interaction, the rain water manages to erode the upper most part of the soil, especially if the soil is not covered with vegetation. Through this direct interaction, we have part of the hydrosphere influencing part of the geosphere, thus interaction between these two spheres.