Which of the following is NOT the assumption of the Revealed Preference Hypothesis?

In standard presentations of Paul Samuelson's Revealed Preference Hypothesis (and its extension by Houthakker), the core formal assumptions/axioms are: (1) Rationality , meaning the consumer prefers larger bundles to smaller ones and behaves purposefully; (2) Consistency , embodied in the Weak Axiom of Revealed Preference (WARP), which states that if bundle A is revealed preferred to bundle B, bundle B is never revealed preferred to A; and (3) Transitivity , embodied in the Strong Axiom of Revealed Preference (SARP), which states that if A is revealed preferred to B and B to C, then A is revealed preferred to C. 'Optimal Choice' is not listed as one of the separate axioms of the Revealed Preference Hypothesis (rather, revealed preference replaces utility-maximizing tangency conditions with observed market choice). Therefore, is the correct answer.