In which situation can urban problems increase even when urban growth rate is low?

Correct answer: When the city's base population is very large and services are limited

The direct answer is A. A growth rate is a percentage, so a low rate applied to a very large population can still produce many additional people. For example, even a small percentage of a large city may represent a large absolute increase. If housing, roads, water supply, sewage systems, schools, hospitals, and waste collection do not expand at the same pace, existing services become overburdened. Option A is correct because it combines a large starting population with limited service capacity, which explains why problems can grow despite a low rate. Option B is wrong because an empty city has no large population pressure. Option C is wrong because excess service capacity would reduce pressure rather than increase it. Option D is generally wrong because a declining population usually reduces demand, although particular problems may still exist. Memory cue: always check both percentage growth and the size of the base population.