The answer is c! I don’t really have much of an explanantion I just know haha
NaCl is dissolved in water so that in a given region or volume the concentration is initially higher in one part than the other l, thus simple diffusion will occur so that there is a net difference or 0, with respect to the concentration of NaCl in a particular volume of water than another. Basically the NaCl will be distributed throughout volume of water.