When I input segment CD onto a graph, I get -0.4 as the slope or 15/-6. If the lines were parallel, they would need to have the same slope which they do not have. If they were perpendicular, they would need to have different slopes so, -2/5 and 5/2 which they do not. That leaves us with the only option of neither.
I took 1.9 and turned it into a fraction and the fraction is 1 9/12 so if you have 11/12 and 1 9/12 then you bought 10/12 more pounds of banana than grapes