The question asks which piece of information would most strengthen the researchers' argument that frequent work breaks, such as browsing the Internet for non-work-related purposes, are rejuvenating and improve concentration, thereby increasing productivity.
Let's analyze the options:
A. Those who were the most productive had jobs that required them to use the Internet frequently for work-related purposes.
-->This option discusses the relationship between productivity and the need to use the Internet for work-related purposes. However, it doesn't directly address the argument about breaks improving productivity, so it doesn't strengthen the argument.
B. Those who took work breaks to browse the Internet were more productive than those who took equally frequent breaks away from the computer.
-->This option suggests that workers who took breaks to browse the Internet were more productive than those who took equally frequent breaks away from the computer. This would strengthen the argument that browsing the Internet specifically, as a form of break, is more effective at improving productivity than other types of breaks. This is a strong contender.
C. Those who abstained from going online during their work day generally took far fewer work breaks than the other workers.
-->This option states that those who abstained from going online took fewer work breaks. This would imply that it's the frequency of breaks, rather than the specific activity of browsing, that contributes to increased productivity. This strengthens the researchers' argument by supporting the idea that taking breaks is important.
D. Those who were the most productive relative to their colleagues tended to take longer work breaks than the least productive of their colleagues.
-->This option mentions that the most productive workers took longer breaks. However, this doesn't directly support the idea that frequent breaks improve productivity, as it focuses on the duration rather than the frequency or type of breaks.
E. Those who spent more than 20 percent of their work day online were less productive, on average, than those who abstained from going online.
-->This option says that spending more than 20 percent of the workday online is associated with lower productivity. While this suggests that there is a limit to how much time can be spent online before productivity decreases, it doesn't directly strengthen the argument that taking breaks, specifically in the form of browsing, improves productivity.
Best Answer: C.
This option directly strengthens the researchers' argument by suggesting that taking more frequent breaks (including browsing the Internet) is associated with higher productivity.