The question asks to identify the correct statement among the given options concerning legal theories.

Hart's View on Rules and Obligation

Option 4 correctly describes H.L.A. Hart's perspective on law. Hart emphasized that for a rule to be considered a legal rule within a system, there must be not only observable conduct conforming to the rule but also an internal point of view. This internal perspective involves the acceptance of the rule as a valid standard of behaviour, meaning individuals believe the conduct is obligatory because it is required by the rule itself.

Analysis of Incorrect Options

Option 1 Analysis

This statement mixes concepts. While natural law deals with reason and nature, equating it as the basis for "imperative law" is inaccurate. Imperative law is typically associated with the command theory of positivism, not natural law principles.

Option 2 Analysis

Natural law is generally not considered a 'command' in the way legal positivists like Austin define law (as commands of a sovereign backed by sanctions). Natural law theories posit that laws derive from morality, reason, or divine order.

Option 3 Analysis

Legal positivists, including Hart, view law primarily as social rules enacted or posited by human beings (e.g., through legislation). While courts interpret and apply law, stating that law is solely 'made through the medium of courts' is an oversimplification and not the core positivist definition.

Conclusion

Option 4 accurately captures Hart's nuanced understanding of legal rules, highlighting the importance of the internal attitude towards rules, signifying their obligatory nature.