24. The author suggests that tax policies be aimed at

答案：[D]preventing the income gap from widening.

解析：该题考查作者的观点，根据题干中的关键词可定位到第六段第一句“Finally, because automation threatens to widen the gap between capital income and labor income, taxes and the safety net will have to be rethought”。由该句可知，由于自动化加大了资本收入和劳动力收入的差距，所以应该重新考虑税收和安全网（保障措施），即税收政策应该避免收入差距扩大，选选项[D]。