A temperature inversion that acts to trap smog in localities such as Los Angeles consists of?

Question

a. cold air above a layer of warm air
b. warm air above a layer of cold air
c. dry air above a layer of moist air
d. moist air above a layer of dry air

Answer 1

A. Cold air layer above a warm layer of air.
The cold air creates a boundary layer trapping the rising warm air. The rising warm air contains the smog and cant rise past the confining cold air that is trying to sink.