A business establishment that engages in over-the-counter sales of products containing ephedrine, pseudoephedrine, or norpseudoephedrine shall:
(1) if the establishment operates a pharmacy licensed by the Texas State Board of Pharmacy, maintain those products:
(A) behind the pharmacy counter; or
(B) in a locked case within 30 feet and in a direct line of sight from a pharmacy counter staffed by an employee of the establishment; or
(2) if the establishment does not operate a pharmacy licensed by the Texas State Board of Pharmacy, maintain those products:
(A) behind a sales counter; or
(B) in a locked case within 30 feet and in a direct line of sight from a sales counter continuously staffed by an employee of the establishment.