The identification of abnormal behavior often relies on the criterion of how rare or uncommon a behavior is, which aligns with the term 'unusualness'. Other criteria such as social deviance, dysfunction, and maladaptive behavior focus on different aspects of behavior. Thus, in this question, 'unusualness' is the relevant term for identifying behaviors based on their rarity. ;
In psychology, abnormal behavior can be identified using various criteria, including 'unusualness', which focuses on rarity. 'Unusualness' highlights behaviors that are statistically rare but not necessarily harmful. For this question, the correct answer is 'C. unusualness.'
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