Modality City has had a severe traffic problem on its streets. As a result, it enacted an ordinance prohibiting all sales to the public of food or other items by persons selling directly from trucks, cars, or other vehicles located on city streets. The ordinance included an inseverable grandfather provision exempting from its prohibition vendors who, for 20 years or more, have continuously sold food or other items from such vehicles located on the streets of Modality City. Northwind Ice Cream, a retail vendor of ice cream products, qualifies for this exemption and is the only food vendor that does. Yuppee Yogurt is a business similar to Northwind, but Yuppee has been selling to the public directly from trucks located on the streets of Modality City only for the past ten years. Yuppee filed suit in an appropriate federal district court to enjoin enforcement of this ordinance on the ground that it denies Yuppee the equal protection of the laws. In this case, the court will probably rule that the ordinance is 
constitutional, because it is narrowly tailored to implement the city's compelling interest in reducing traffic congestion and, therefore, satisfies the strict scrutiny test applicable to such cases.  constitutional, because its validity is governed by the rational basis test, and the courts consistently defer to economic choices embodied in such legislation if they are even plausibly justifiable.  unconstitutional, because the nexus between the legitimate purpose of the ordinance and the conduct it prohibits is so tenuous and its provisions are so underinclusive that the ordinance fails to satisfy the substantial relationship test applicable to such cases.  unconstitutional, because economic benefits or burdens imposed by legislatures on the basis of grandfather provisions have consistently been declared invalid by courts as per se violations of the equal protection clause of the Fourteenth Amendment. 