C) Freedom of speech is at issue in this case.
Step-by-step explanation:
Freedom of speech is one of the fundamental rights of human. Freedom of speech offers freedom to the individual or public to express their views, opinions and ideas without fear.
Everybody have rights to express their ideas and information in-spite of government restrictions. "First Amendment" laid by the constitution of Unites States of America in the year 1789 gives the people the freedom of speech.
In the above scenario, a man burns the American flag. His activity was offensive and unacceptable in the public square.