The correct answer is A. A solid surface.
Step-by-step explanation
The Moon is a natural satellite of the Earth with a solid surface characterized by its immense craters originated by the collision of meteorites and flying objects. Also, it has a surface with different types of rocks. The case of planet Earth is composed of several layers of rocks, some are liquid, and as they approach the surface they are more solid like the soil in which all life occurs. Therefore, it can be stated that the Earth and the Moon have solid surfaces. So the answer is A.