Politician: Over the next decade, our city will be replacing all of its street signs with signs that are designed for improved readability. But since no one is complaining about the current signs, installing the new ones is a colossal waste of time and money. Which one of the following would be most useful to know in evaluating the politician's argument? ['What percentage of its street signs does the city replace annually in the course of ordinary maintenance?', 'What features of the new street signs improve the readability of the signs?', 'Do any other cities plan to replace their street signs with signs designed for improved readability?', 'Are the new street signs considerably more expensive to manufacture than the current street signs were?']