ok I figured this question out but only by trial and error. I noticed in the diagram. it was already figured out that "I" could not have four stars. I'm curious into what people did to see this inference up front.
After having read the question, and quickly looking at our rules, we can see I is not a CD that can have four stars. We know that I must share a spot with either H or R. Since we are capped out at 2 per rating, that would not allow Q to be with that group. At this point, we would have at least 2 CDs with a higher rating.