Which definition for the word topography can be determined using context clues from this passage?
The National Weather Service continuously broadcasts warnings and forecasts that can be received by NOAA Weather Radios, which are sold in many stores. The average range is 40 miles, depending on the region's topography. Tall mountains, of course, might mean that the signal has a smaller range.
the number of radio signals in an area
the population of an area
the language spoken in an area
the surface features of an area