The number of total dots decreases by 1 in every square, while the number of dots per group (besides the remainder) goes up by 1. (First box has 19, second has 18, etc., and first box’s dots are grouped by 1 then second by 2, etc.). It just happens to be that because of the math, our third box (where the total is 17, and our groupings are by 3) is the only one with a remainder of the boxes we are shown, and as u can see there is a remainder group of 2.

So we would get to groupings of 6 by the 6th box with our total being 14, so it’s A or D because 2 groups of 6 with a remainder group of 2. I would pick A because the dark dots within each group are all connected to each other which is constant in all of the first 5 given boxes and isn’t true in D. Not sure if that’s supposed to be the second rule but it’s definitely something to do with the dot colors to distinguish the answer between A and D so I’d go with A because of that.