What results when nitrogen dioxide and hydrocarbons react in the presence of sunlight?

What results when nitrogen dioxide and
  hydrocarbons react in the presence of sunlight?
  a. photochemical smog
  b. industrial smog
  c. a thermal inversion
  d. depletions of the ozone layer
  e. any of these

Question 2

Thermal inversions
  a. enhance the movement of pollutants into the
  upper reaches of the atmosphere.
  b. are characteristic of the atmosphere over
  extensive stretches of land, such as prairies.
  c. occur as temperature changes between daytime
  and nighttime.
  d. occur when warm air is trapped between layers
  of cool air.
  e. occur when warm air rises through layers of
  cooler air.