Since the city council sent a letter to the residents of Newport on the danger to the environment of smoke from beach firepits, residents have cut their use of beach firepits by 20 percent. Obviously the city council's letter was responsible for the residents' decision to reduce their consumption of firewood.
Conclusion: City council's letter is responsible for residents' decision to reduce the consumption of wood.
The author relies on which one of the following to advance his argument?
A) When it sent the letter, the city council predicted a reduction in the consumption of firewood.
Negation: When it sent the letter, the city council did not predict a reduction in the consumption of firewood
Analysis: Doesn't matter. What if they had predicted? The outcome would still be the same.
B) The cost of firewood has not increased significantly in Newport since the city council sent the letter.
Negation: The cost of firewood has increased significantly since the council sent the letter
Analysis: If the cost has increased significantly, then probably it is not the city council's letter that resulted in decrease in the consumption of fireweed, but the increased prices. Keep it!
C) Danville, a city 10 miles from Newport also experienced a drop in the use of beach firepits.
Doesn't matter. Could the consumption in Newport still be reduced had Danville didn't experience a drop in the use of beach firepits? Yes!
D) Previous initiatives by the city council to preserve the environment have been well-recieved in the town of Newport.
Doesn't matter. Could the consumption in Newport still be reduced had the city council's previous initiatives been objected to? Yes!
E) Gas burning barbeques have become more popular on the beaches of Newport.
This could be a sufficient condition but not a necessary condition. It means, if this statement is true, it would support the conclusion. But it is not required for this statement to be true to reach to the conclusion.
Therefore,
the answer is B