The correct answer is - c. a steeper slope.
When the contour lines on a topographic map are very close it means that there is a steeper slope. The contour lines are a very good, easy, and efficient way of depicting the relief; the closer the contour lines are, the steeper the place, the further away the contour lines are, the flatter the place. On certain places where the steepness is to big (usually a vertical fall) instead of using the standard contour lines, there are special ones that are like small stripes directed into the direction of fall, which is also very well represented and very helpful.
