When you are talking to someone and you want a certain phrase you said to stand out, you emphasis your words. That is pretty much the same case here. A is incorrect because that is capturing a model of some sort, B is incorrect because that would be an equal blend of all colors together, and D is incorrect because you are not uniting the colors, you want the elements to stand out. Emphasis is achieved usually by using mostly dark colors then a splash of something such as neon pink or yellow.
A,b,c they can all support someone that is in need and facing substance abuse problems
Value The lightness or darkness of tones or colors. White is the lightest value; black is the darkest. The value halfway between these extremes is called middle gray. Space An element of art by which positive and negative areas are defined or a sense of depth achieved in a work of art .