Its a ... pentatonic scale , hope this helps :)
art that does not portray figures or objects; art without real models or subject ... on formal elements (the visual elements, design principles) to carry its message ... elements, such as a line, shape, color, texture, that are used by artists to create imagery ... using a series of closely spaced parallel lines to achieve a similar effect.
From looking at the painting, I would say that the best answer is C, the designer uses different colors to create contrast.
It is definitely not A because the apron has different colors, not repeating colors.
