1. After examining studies indicating that drinking soda pop was directly related to the incidence of tooth decay, the legislature of the state of Tenacka enacted a law prohibiting the advertising of any soda pop in all media. This included radio, television, and any advertisement on the internet. Which of the following is the clearest reason for holding the law to be unconstitutional?
   1. A state may not interfere with commercial speech.
   2. The sale of soda pop frequently involves interstate commerce.
   3. The law imposes a prior restraint on publication.
   4. There are less restrictive ways of protecting the public against tooth decay which would be equally effective.