Possession of more than twenty-four grams of a methamphetamine precursor drug or combination of methamphetamine precursor drugs calculated in terms of ephedrine HCl and pseudoephedrine HCl is prima facie evidence of intent to violate sections 19-03.4-03 and 19-03.4-04. This section does not apply to a practitioner as defined in section 19-03.1-01 or to a product possessed in the course of a legitimate and lawful business.