The National Ambient Air Quality Standards

The National Ambient Air Quality Standards:

A) were met for the six basic pollutants by the early 1990s
B) are to be established taking into account the economic and feasibility of the pollution controls necessary to be implemented to protect the public health and welfare
C) can be postponed by a federal variance for major emitting facilities if the owner can demonstrate that the standards will pose a significant financial burden
D) are established by taking into account the public health and welfare taking into account an adequate margin to allow companies to maintain reasonable profits
E) none of the other choices