Officials of the town of Sunnyville were concerned about the number of dogs running loose. They set up a new administrative agency called “Dog Control.” The new agency issued a regulation that all dogs must be on leash in public. Tony who had moved to Sunnyville in the previous month did not own a dog and had no plans to get one. He, however, thought the regulation was outrageous and decided to sue on the basis that it was not validly enacted. Mona, another resident, was also concerned about the law. She rents a home with a fence in the backyard that was in public view. She was concerned that the regulation would be applied to her dogs while in the fenced area. She decided to bring a preemptive strike and sue the city for revocation of the regulation before the city could sue her. Both Tony and Mona rush to file suit before the city has a chance to take any action to enforce the new rule. Of the following arguments, which is the best for the city to raise in the lawsuit brought by Mona?