I think it would be graph A, because she wants to show a slight decrease in the number of faulty products over the 8 month period. If you look at the lines on the graphs, although they show the same data, because the increments on the y axis are more spread on graph B, the line appears steeper. The line appears more gradual on graph A, which would show a "slight decrease." The steeper line on graph B makes the decrease SEEM larger, but it isn't.