[求助]JJ about rail system

I found the following question in this month JJ but not sure the answer.  please advise.

A recent poll found that over 80 percent of the residents of Nalmed Province favored a massive expansion of the commuter rail system as a means of significantly easing congestion on the province's highways and were willing to help pay for the expansion through an increase in their taxes. nevertheless, the poll results indicate that expansion of the rail system, if successfully completed, would be unlikely to achieve its goal of easing congestion, because______ A. most people in favor of expanding the rail system reported less congestion during their highway commute as the primary benefit they would experience B of the less than 20 percent of residents not counted as favoring the expansion, about half claimed to have no opinion one way or the other C. the twice-daily periods of peak congestion caused by people commuting in cars have grown from about an hour each to almost two and a half hours each in the past 20 years D expanding the commuter rail system will require the construction of dozens of miles of new railed E the proposed expansion to commuter rail system will make it possible for some people who both live and work at suburban locations to commute by rail.

A recent poll found that over 80 percent of the residents of Nalmed Province favored a massive expansion of the commuter rail system as a means of significantly easing congestion on the province's highways and were willing to help pay for the expansion through an increase in their taxes. nevertheless, the poll results indicate that expansion of the rail system, if successfully completed, would be unlikely to achieve its goal of easing congestion, because______

A. most people in favor of expanding the rail system reported less congestion during their highway commute as the primary benefit they would experience

B of the less than 20 percent of residents not counted as favoring the expansion, about half claimed to have no opinion one way or the other

C. the twice-daily periods of peak congestion caused by people commuting in cars have grown from about an hour each to almost two and a half hours each in the past 20 years

 D expanding the commuter rail system will require the construction of dozens of miles of new railed

 E the proposed expansion to commuter rail system will make it possible for some people who both live and work at suburban locations to commute by rail.

A

gwd上面题

Everyone thinks that the highway will be good again after the rail system is completed. Then they will continue to drive on the highway. As a result, the highway will be congested again. Pay attention to "the primary benefit"

heres my opinion

Premise: 80% people favor the expansion, because it will ease their commute.

Conclusion: poll result indicates that it will not achieve the goal (premise) if the rail system expansion completes.

Question: why?

possible answer: these people who favored the expansion do not favor anymore, or they dont consider expansion a means of easing congestion anymore. what has happened? the reasons could be 1) railway system is not preference; 2)tax is too heavy to afford

one of 7 habits is : begin with end in mind. I think this one is very suitable for GMAT RC, SC, and CR

A.
most people in favor of expanding the rail system reported less
congestion during their highway commute as the primary benefit they
would experience

B
of the less than 20 percent of residents not counted as favoring the
expansion, about half claimed to have no opinion one way or the other

20% residents do not favor it,  50%*20% residents do not care about it. => at most 10% residents would disaprove the expansion. remember, there are 80% residents favor the project.

So B will not significantly affect the results of poll.

        

C.
the twice-daily periods of peak congestion caused by people commuting
in cars have grown from about an hour each to almost two and a half
hours each in the past 20 years

you can conceive this one as supportive statement to the poll results. but, actually, this one is some kind of irrelevant

 D expanding the commuter rail system will require the construction of dozens of miles of new railed

this one is absolutely irrelevant

 E
the proposed expansion to commuter rail system will make it possible
for some people who both live and work at suburban locations to commute
by rail.

still irrelevant