Serene City enacts an ordinance that bans the use of "sound amplifying systems" on public streets. Tyler wants to campaign for a seat on the city council by broadcasting his message through speakers mounted on a truck. In Tyler's suit against the city, a court would likely hold the ordinance to be

a. justified by the need to protect individual rights.

b. constitutional under the First Amendment.

c. necessary to protect national interests.

d. an unconstitutional restriction of speech.