How do impact craters reveal a surface’s geological age? ?

Scientists record the size and number of impact craters and how eroded they are to determine the ages and histories of different planetary surfaces.Older surfaces have been exposed to impacting bodies (meteoroids, asteroids, and comets) for a longer period of time than younger surfaces. Therefore, older surfaces have more impact craters. 

The sun's parallax would be 180 degrees, greater than which you can't get.  so a. would be your anwser