The conclusion in the last sentence of the passage is that it would hardly be reasonable to expect the mayor to attempt to slow the forces of technology in response to the growing inequality in wages between college and high school graduates. To cast doubt on this conclusion, we need to find an option that suggests that there were alternative actions or policies the mayor could have taken to address the problem without trying to slow technological trends.
Option (A) casts the most serious doubt on the conclusion because it suggests that the mayor could have initiated policies to make it easier for less-educated workers to receive the education necessary for better-paying jobs. This implies that there were practical steps the mayor could have taken to address the inequality issue without attempting to slow down technology.
Option (B) mentions increasing funding for employment for high school graduates, which addresses job placement but doesn't directly challenge the conclusion regarding technological trends.
Option (C) talks about generating more demand for products from high blue-collar wage industries, which is a different approach but doesn't directly challenge the conclusion about the mayor's response to technological trends.
Option (D) discusses tax rates on the wealthiest earners, which is related to revenue distribution but doesn't directly challenge the conclusion about the mayor's response to technological trends.
Option (E) mentions protecting city workers' earnings from foreign competition, which is another approach but doesn't directly challenge the conclusion regarding the mayor's response to technological trends.
So, option (A) provides the most significant challenge to the conclusion by suggesting an alternative action the mayor could have taken to address the inequality issue without attempting to slow down technology.