13. Wood smoke contains dangerous toxins that cause changes in human cells. Because wood smoke presents such a high health risk, legislation is needed to regulate the use of open-air fires and wood-burning stoves.
Which of the following, if true, provides the most support for the argument above?
A.The amount of dangerous toxins contained in wood smoke is much less than the amount contained in an equal volume of automobile exhaust.
B.Within the jurisdiction covered by the proposed legislation, most heating and cooking is done with oil or natural gas.
C.Smoke produced by coal-burning stoves is significantly more toxic than smoke from wood-burning stoves.
D.No significant beneficial effect on air quality would result if open-air fires were banned within the jurisdiction covered by the proposed legislation.
E.In valleys where wood is used as the primary heating fuel, the concentration of smoke results in poor air quality. 答案E. 我认为B也支持啊：因为立法限制，所以most heating and cooking is done with oil or natural gas.脑筋转不过弯来，请各位指教。 | 
