Which of the following is NOT true about ozone (O3)?
a. Is an important component of the upper atmosphere by asorbing much of harmful UV rays.
b. Is harmful component of lower atmosphere by causing respiratory problems associeated with smog.
c. Is readily broken down in upper atmopshere by methane (CH4), chlorofluorocarbons (CFCs) and nitrous oxides (Nx0).
d. Is a major contributor to 'global warming'.