Which of the following propositions do not suit the approaches of American Realism?

American Legal Realism insists on keeping the descriptive study of what courts actually do separate from normative prescriptions about what law ought to be, so the proposition "It combines the 'is' and 'ought' aspects in the study of law and how it works." runs contrary to its method, whereas "It lays emphasis on empirical study of the behaviour of judges." and "It distrusts the sufficiency of legal rules and concepts as descriptive of what Courts do." describe it accurately.