Which of the Following Statements About Temperature Inversion Is NOT

Which of the following statements about temperature inversion is NOT true?

A) Temperature inversion causes a layer of warm air to trap a cooler layer of smog in an area.
B) Sunny climates with light winds are at a decreased risk for temperature inversion.
C) Large cities located in valleys surrounded by mountains are at an increased risk for temperature inversion.
D) If a temperature inversion lasts more than a few days, pollutants at ground level can build up to dangerous levels.