Why is the "the african queen" a classic?

Hollywood classics don't get much more classic or Hollywood than The African Queen, John Huston's 1951 adventure-romance

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.