Explanation

Sorry, I meant this for question number 4. Please disregard this question. Thank you!

@Boram, I see that you meant this for #4. In any case, I'll still provide an explanation for this question since others may have questions on it. The question asks, "According to the passage, which one of the following is true of Carroll’s study?" The key portion of the text to look at is where Carroll's views are shown, which is in the second half of the first paragraph. In line 18, the passage states, "Carroll argues that right-to-work laws 'do matter' in that such laws generate differences in real wages across states.'" (C) says, "It argues that right-to-work laws have affected wages in right-to-work states." The whole goal of Carroll's study was to show that these right-to-work laws have had an impact in right-to-work states. We have explicit text support to back this up, and this is the correct answer choice. Hope this helps. Let us know if you have any other questions!