The appropriate answer would be:
d No violation of the Constitution has occurred
The First Amendment protects the right to peaceful assembly and free speech. However, the right to protest does not protect violent behavior or actions that pose a threat to public safety. When the protest escalated into violence, vandalism, looting, and resulted in injuries and a death, the police had the responsibility to maintain order and ensure public safety. Thus, declaring the protest a riot and shutting it down can be seen as a necessary action to protect the community, rather than a violation of constitutional rights.