fares on the city-run public buses in Greenville are subsidized by city tax revenues, but among the beneficiaries of the low fares are many people who commute from outside the city to jobs in Greenville. Some city councilors argue that city taxes should be used primarily to benefit the people who pay them, and therefore that bus fares should be raised enough to cover the cost of the service.
Each of the following, if true, would weaken the argument advanced by the city councilors EXCEPT:
(A) Many businesses whose presence in the city is beneficial to the city’s taxpayers would relocate outside the city if public-transit fare were more expensive.
(B) By providing commuters with economic incentives to drive to work, higher transit fares would worsen air pollution in Greenville and increase the cost of maintaining the city’s streets.
(C) Increasing transit fares would disadvantage those residents of the city whose low incomes make them exempt from city taxes, and all city councilors agree that these residents should be able to take advantage of city-run services.
(D) Voters in the city, many of whom benefit from the low transit fares, are strongly opposed to increasing local taxes.
(E) People who work in Greenville and earn wages above the nationally mandated minimum all pay the city wage tax of 5 percent.

D..

Careful:This is an EXCEPT question.

A, B, C and E all weaken the conclusion.

B - Weakens the argument by showing that the increased fare will result in increased maintenance costs.
C - Weakens the argument by showing that a section of the public is adversely affected.
E - Weakens the argument by showing that even people who commute from outside the city contribute to taxes. This directly attacks the justification for the fare increase by nullifying the following portion of the argument.

but among the beneficiaries of the low fares are many people who commute from outside the city to jobs in Greenville. Some city councilors argue that city taxes should be used primarily to benefit the people who pay them, and therefore that bus fares should be raised enough to cover the cost of the

As you said, D doesn't weaken the argument. Thats why D is the answer.

one more D

No. The correct answer in a weakens except question does not need to strengthen. In EXCEPT questions, we want to find a logically opposite answer.

The logical opposite of Weaken is not necessarily 'Strengthen'
The logical opposite is 'Not Weaken'.

Similarly, in 'Strengthen Except' questions, the correct answer does not need to Weaken the argument. A neutral answer that neither strenghtens nor weakens the argument is also a valid candidate.

Doh! I need to read more carefully. Definitely D.

'D'

Voters of the city are willing to pay higher bus fare but against increasing city taxes, which is aligned with the proposal of council members.

Another D