When a city experiences a sharp decline in population, the city' s tax revenues, which pay for such city services as police protection and maintenance of water lines, also decrease. The area to be policed and the number and length of the water lines to be maintained, however, do not decrease. Attempting to make up the tax revenue lost by raising tax rates is not feasible, since higher tax rates would cause even more residents to leave.
The information given most strongly supports the general claim that if, in a city with sharply declining population, police protection and water line maintenance do not deteriorate, some other service previously provided by the city will deteriorate or be eliminated.