In 1986, the city of Los Diablos had 20 days on which air pollution reached

unhealthful amounts and a smog alert was put into effect. In early 1987, new

air pollution control measures were enacted, but the city had smog alerts on

31 days that year and on 39 days the following year. In 1989, however, the

number of smog alerts in Los Diablos dropped to sixteen. The main air

pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the

levels of both have been monitored by gas spectrography.

Which of the following statements, assuming that each is true, would be LEAST

helpful in explaining the air pollution levels in Los Diablos between 1986

and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put

into effect in November of 1988.

(B) In December of 1988 a new and far more accurate gas spectrometer was

invented.

(C) In February of 1989, the Pollution Control Board of Los Diablos revised the

scale used to determine the amount of air pollution considered unhealthful.

(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign

donations from local industries and to have exempted those same industries

from air pollution control measures.

(E) Excess ozone and carbon monoxide require a minimum of two years to break

down naturally in the atmosphere above a given area.

正确答案是(B)

是否因为新发明的gas spectrometer应该使1988和1989年的pollution levels都下降?

另外,答案选项(D)似乎也可以是答案

因为(D)所描述的"污染免列"是发生在1988年

如同正确选项(B)

(D)也无法解释为何1988年pollution levels没有下降,不是吗?

No answer for this question, Let me bring it up again.

No idea for this, what is the type of this sort of question.