Which of the Following Definitions Represents Internet Censorship

Which of the following definitions represents Internet censorship?

A) a problem that occurs when someone registers purposely misspelled variations of well-known domain names
B) the theft of a website's name that occurs when someone, posing as a site's administrator, changes the ownership of the domain name assigned to the website to another website owner
C) government attempts to control Internet traffic, thus preventing some material from being viewed by a country's citizens
D) an anti-spamming approach where the receiving computer launches a return attack against the spammer, sending email messages back to the computer that originated the suspected spam