单选题 A substantial hike in the top rate of income tax would not solve this problem but merely aggravate the nation"s already waning support.

【正确答案】 C

【答案解析】[解析] 题干：大量增加所得税的最高税率解决不了问题，反而只会降低人们对国家本已吝啬的支持。wane衰退，减弱；decline下降；depreciate贬低，降职；warn警告，通知；startle震惊。根据题意，选项C为正确选项。