Assertion (A): A common principle about Criminal Law is that, unless an activity is prohibited by law, it does not qualify as a crime.
Reasoning (R): Crime as a concept is so broad that there is no single, universally accepted definition to it.

Both A and R are correct and R is not the correct explanation of A.

The term 'Crime' denotes an unlawful act and this unlawful act is punishable by a state. Crime as a concept is so broad that there is no single, universally accepted definition to it. But, for the sake of convenience, several countries provide statuary definitions of various kinds of unlawful activities, which can be identified as crimes. A common principle about Criminal Law is that, unless an activity is prohibited by law, it does not qualify as a crime. Incidents of crime hurt not only the individual, but also the state. Therefore, such acts are forbidden and punishable by law. The body of laws which deals with imposing punishments on crimes is known as Criminal Law.