What is the name for a hanging fabric stretched taut between upper and lower pipes and curved to surround the rear and sides of the stage and colored with various colors in part to represent a series of skyscapes

i would say the answer is b. zigzag lines of the leaves. i believe this is the answer because zigzag lines go in different direction while the other options like: the vertical lines of the trees, the dotted lines on the road, and the curved lines of the park benches go in one direction.

the answer is backup