Which of the following statements about smog is/are correct?
$(i)$ Smog formed on sunny days contains oxidizing molecules.
$(ii)$ Photochemical smog contains many reactive molecules.
$(iii)$ The main polluting components of smog are oxides of carbon.
$(iv)$ The presence of carbon monoxide in air leads to the formation of ozone in smog.

• A
  $(i)$,$(iii)$
• B
  $(i)$,$(ii)$
• C
  $(ii)$,$(iv)$
• D
  Only $(ii)$