Frodo and Sam are studying a topographic map of Mordor. Place the letter describing contour lines on a map to the left of the number describing a possible goal.

 1. If Frodo and Sam want to find a level route, they should look at:
 2. If Frodo and Sam want to go directly uphill, they should go:
 3. If Frodo and Sam want to find Mount Doom, they should look for:
 4. If Frodo and Sam want to find the River Anduin, they should look for:

A. Single contour lines
B. Concentric contour lines
C. Perpendicular to the contour lines
D. Parallel contour lines