4. The client was riding in a car that hit a tree. The head hit the windshield (coup) and then the brain rebounded within the skull toward the opposite side (contrecoup).
What injury is this?

The answer is d., a mountain.

  the  peripheral nervous system consists of all of the nerves that lie outside the brain and spinal cord.

The highest point of a hill (or mountain) is a single point.
a single point can only be precisely marked with a dot. 
putting on a contour line is impossible  on a single point because the contour line is created after multiple points that have the same hight are marked, and after that, all of those points are connected with a line that creates a closed area. so the highest point, as said above, is a single point, there are no other points with the same height, so the only possible way for it to be marked is with a dot, and there is no possibility for a contour line.