The usage of white lines retreating towards the top of the image creates the illusion of

pattern
emphasis
balance
movement

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.

a fashion movement

sorry if this is wrong