What does the paint death of marat depict

"the way it took the stuff of politics as its material, and did not transmute it".

answer; i believe the correct answer is "he who gladly serves"

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.