It would be 2D art due to the flat surface area of the side walk. but if you have very good art skills you can make it look 3D
Maybe something like crystal I think, but out of yours I would pick karma!
Oil paint because it has the consistency of pigments mixed with drying oil (commonly linseed oil). The oil paint drys more slowly which makes it more easy to blend each color together & provided a softer merging of one tone into the next, becoming a well used tool to artist.
