Which of the Following Definitions Represents Teergrubing

Which of the following definitions represents teergrubing?

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.