The argument claims that the decline in the Alternative Energy Action party's fortunes from 1988 to 1992 shows that alternative energy concerns faded in significance during this period, even though the party's core manifesto remained unchanged.
To weaken this argument, we need evidence that the party’s decline in support is not due to fading of alternative energy concerns in the town. Let's evaluate each option:
(A)
Between 1998 and 1992, the number of eligible voters in Sunnyville rose, but not the percentage who actually voted.
This doesn't address the core issue.
(B)
Between 1988 and 1992, Sunnyville’s leading political party revised its platform, adopting the policies of the Alternative Energy Action party.This would weaken the argument significantly. If the leading political party adopted the same alternative energy policies as the Alternative Energy Action party, it could explain why the latter lost support: voters may have felt the concerns were being addressed by another, more established party.
This suggests that alternative energy concerns were still important, but voters shifted to another party that shared similar views.
(C)
The parties that ran candidates in the 1992 election in Sunnyville were the same as those that had done so in the 1988 election.This doesn't directly weaken the argument. Same or different Candidatures does not decide the energy concerns.
(D)
In 1992, the Alternative Energy Action party won fewer votes in Sunnyville than it had won in 1988.This is consistent with the argument and doesn't weaken it. It simply reaffirms the decline in the party's fortunes.
(E)
Between 1988 and 1992, some measures intended to provide alternative energy had been adopted by the town council, but with inconclusive results.Irrelevant option
The correct answer is (B). It provides a reason for the party's decline in support that doesn't rely on the fading significance of alternative energy concerns. Instead, it suggests that voters turned to the leading political party, which adopted the same policies.