None of the actions proposed will make a significant difference to air quality. The biggest improvement will come from the gradual replacement of older vehicles with new ones built to a higher emissions standard and, ultimately, the introduction of hybrid and electric vehicles.
If you want to do anything in a faster time frame than that then steps must be taken to: reduce traffic congestion; avoid building new homes in areas that are already congested; build new homes in areas where the air quality is good.
You may as well stay with option A since options B and C will make no difference. I previously submitted a much more comprehensive plan for traffic management in the centre of Rayleigh which does address the congestion and air quality hot spots.