Given below are two statements:
Statement $I:$ Classical smog occurs in cool humid climate. It is a reducing mixture of smoke,fog and sulphur dioxide.
Statement $II:$ Photochemical smog has components,ozone,nitric oxide,acrolein,formaldehyde,$PAN$ etc.
In the light of above statements,choose the most appropriate answer from the options given below:

• A
  Both Statement $I$ and Statement $II$ are correct
• B
  Both Statement $I$ and Statement $II$ are incorrect
• C
  Statement $I$ is correct but Statement $II$ is incorrect
• D
  Statement $I$ is incorrect but Statement $II$ is correct