Answer
From most positive to most negative the situations ranked: b,a,c,d.
Work Step by Step
When viewing a force vs. distance graph, the area between the line and the x-axis is the work being done. If the line is in the negative quadrant, then the work is negative. Although there are no numbers, the graphs are clear enough to show that situation (b) has the greatest positive area. The next is graph (a) which shows equal positive and negative areas, so there is no work being done. Although both situations (c) and (d) have net negative work, graph (d) clearly has a greater negative area so there is a more negative amount of work being done on graph (d). Situation (b) has positive work; situation (a) has no work; situation (c) has negative work; and situation (d) has even greater negative work.