If a city's population grows by 13 percent while sewage-treatment capacity rises by only 4 percent, which outcome is most likely?

Correct answer: Pressure on per-capita capacity and risk of untreated waste may increase

Sewage-treatment capacity must be compared with the amount of wastewater produced. Here, population increases by 13 percent, but treatment capacity increases by only 4 percent. If people continue to produce roughly the same amount of wastewater per person, the total load grows much faster than the system’s ability to treat it. Per-person capacity therefore falls, even though the absolute capacity has increased.

Option A follows directly from this imbalance. More pressure may produce overloading, untreated discharge, overflow, or poorer treatment, although the exact outcome depends on water use, infrastructure, and management. Option B is opposite to the likely effect, C incorrectly assumes population growth reduces waste, and D ignores the direct relationship between population, wastewater generation, and treatment demand. Thus A is the best choice.