Answer:
Antitrust law
Explanation:
Alonzo is using antitrust law to prevent the union strike.
Antitrust law regulates competition among firms, and its main goal is to prevent the formation of monopolies. A monopoly is a firm that is the sole seller of a product in a determined market.
Alonzo is saying that if his Cake Shop entered a strike, the only other Cake Shop in the region would become a monopoly, effectively violating antitrust law.