Maple City has an ordinance that prohibits the location of "adult theaters and bookstores" (theaters and bookstores presenting sexually explicit performances or materials) in residential or commercial zones within the city. The ordinance was intended to protect surrounding property from the likely adverse secondary effects of such establishments. "Adult theaters and bookstores" are freely permitted in the areas of the city zoned industrial, where those adverse secondary effects are not as likely. Storekeeper is denied a zoning permit to open an adult theater and bookstore in a building owned by him in an area zoned commercial. As a result, Storekeeper brings suit in an appropriate court challenging the constitutionality of the zoning ordinance. Which of the following statements regarding the constitutionality of this Maple City ordinance is most accurate? 
The ordinance is valid, because a city may enforce zoning restrictions on speech-related businesses to ensure that the messages they disseminate are acceptable to the residents of adjacent property.  The ordinance is valid, because a city may enforce this type of time, place, and manner regulation on speech-related businesses, so long as this type of regulation is designed to serve a substantial governmental interest and does not unreasonably limit alternative avenues of communication.  The ordinance is invalid, because a city may not enforce zoning regulations that deprive potential operators of adult theaters and bookstores of their freedom to choose the location of their businesses.  The ordinance is invalid, because a city may not zone property in a manner calculated to protect property from the likely adverse secondary effects of adult theaters and bookstores. 