This forest plot illustrates the results of studies that evaluated treatment response after 24 hours (4 studies) and 28 days (2 studies). Use the forest plot to answer the following question. Concerning the two studies that evaluated treatment response at 28 days, what does the size of the square tell you about the Popova et al study? This study was the most biased This study was the least biased This study had the least participants This study had the most participants