Which of the Following Statements Is True

Which of the following statements is true?

A) Thermal inversion occurs when a layer of cold air prevents warm air from rising.
B) Thermal inversions exacerbate pollution problems.
C) Thermal inversions last only a few minutes to a few hours.
D) Normally, cool air near Earth's surface expands and rises, carrying pollutants higher into the troposphere.
E) Thermal inversions help prevent air pollution.