(D) says, "It confuses a condition that is necessary for establishing the truth of the conclusion with a condition that is sufficient for establishing the truth of the conclusion."
The problem with (D) is that there is not any conditional logic contained within the stimulus, so there are no sufficient or necessary conditions. Thus, (D) is out, as the stimulus just shows a correlation between two things.
Does this make sense? Let us know if you have any other questions!