When chance, bias, and confounding have been ruled out as alternative explanations for an association, we may conclude that the association is causal?

True. By ruling out chance, bias and confounding, you can be able to determine that the association that is observed in the study is valid. These is because these are the main alternative explanations that can rule out that the association is causal

answer; john stuart mill's principle of utility is your answer; /// good luck

you answered your own : -/