I think the answer is A.
Mayor of Plainville: In order to help the economy of Plainsville, I am using some of our tax revenues to help bring a major highway through the town and thereby attract new business to Plainsville.
This tells us in order to help the economy Mayor is using tax revenue for building the highway. We do not know if mayor owns land around the newly built highway. We do not know if his voter base is residing in that area. Mayor says A but his motive may be to achieve B.
Citizens' group: You must have interests other than our economy in mind. If you were really interested in helping our economy, you would instead advocate the revenues to building a new business park, since it would bring in twice the business that your highway would.
This tells us there is another way to help the economy and mayor is not choosing the shortest path to improving the economy.
Which one of the following principles, if accepted, would most help the citizens’ group to justify drawing its conclusion that the mayor has in mind interests other than Plainsville’s economy?
(A) Anyone really pursuing a cause will choose the means that that person believes will advance the cause the farthest. - this is what citizens are saying mayor is not taking the route that will improve the economy two times more but he is taking a route that will only be half as good. So citizens believe anyone really pursuing a cause will take actions that will increase the chance of success to the maximum.
(B) Any goal that includes helping the economy of a community will require public revenues in order to be achieved.- I don't think Any in the starting makes any sense. It is too extreme and involves all goals will require public revenue. There ought to be a way that does not require public spending to improve the economy. Besides this is not what citizens are saying. THey are saying Mayor has hidden agenda.
(C) Anyone planning to use resources collected from a group must consult the members of the group before using the resources. - Citizens are not saying mayor consult them or not.
(D) Any cause worth committing oneself to must include specific goals toward which one can work. - Well again too off the point from Citizen's views.
(E) Any cause not pursued by public officials, if it is to be pursued at all, must be pursued by members of the community. -no Citizens do not want to purse what public officials ignore. Sometimes Courts can intervene. Again this is not something Citizens are saying.