Argument: A recent study showed that students who regularly consume energy drinks perform worse on standardized tests than students who do not. Therefore, schools should ban energy drinks to improve students' test scores. Which of the following, if true, would most weaken the argument?
✓ Correct Answer: Option A
If students consuming energy drinks also have a confounding factor (like sleep deprivation from late-night studying), then poor test performance might be attributed to the lack of sleep, not the energy drinks, weakening the causal claim.