Which strategy is NOT likely to protect groundwater? 

A)  using advanced sewage treatment 
B)  monitoring aquifers near landfills and underground tanks 
C)  banning disposal of hazardous wastes in sanitary landfills and deep-injection wells 
D)  requiring liability insurance for old and new underground tanks

Coal burning,diesel engines,and open fires produce ___________________________________,which may be the second largest contributor to global warming.