Why is the surface of the Moon full of pockmarked craters?
a) It has little weathering to erode them.
b) Due to meteorites landing on them
http://spaceplace.nasa.gov/craters/en/
So is the answer (2) ?
Yes.
The surface of the Moon is full of pockmarked craters primarily because of meteorite impacts. The Moon lacks a significant atmosphere, which means that there is no protection from incoming objects in space. When meteors, asteroids, or comets collide with the Moon's surface, they create impact craters.
To verify this information, you can search for scientific studies, articles, or documentaries about the Moon's craters. Websites of space agencies like NASA or the European Space Agency often provide detailed information about lunar features. Reading books or articles written by experts in planetary science or astronomy can also help you understand the process of crater formation on the Moon's surface.