Which of the following correctly explains how selective incorporation contributed to the right to freedom of speech in the United States?
a) Selective incorporation gradually applied the protections of the First Amendment, including freedom of speech, to state governments through the Fourteenth Amendment's due process clause.
b) Selective incorporation restricted the right to freedom of speech to only certain categories of individuals based on their social status and occupation.
c) Selective incorporation enhanced the power of state governments to regulate freedom of speech without federal intervention.
d) Selective incorporation abolished the right to freedom of speech in the United States, replacing it with a system of government censorship.