Antiwar protest song was a dominant music theme in the 1960's and 1970's. The 1960's gave rise to many alternative culture and social groups, such as the hippies and the New Left. The controversial war in Vietnam resulted in many marches and demonstrations during which the protest songs were sung. Many of the protest songs were banned from mainstream radio station and were heard on underground radio stations only.
The most famous author of antiwar protest songs in that period was Bob Dylan. He produced a number of landmark protest songs such as: 'Blowing in the wind' and ' Master of War'.
B. None of these are examples of permissible limitations on the freedom of speech - this is the answer that represents an instance where the government can/or can't limit what people say.
