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 antispamming approach where the receiving computer launches a return attack against the spammer,sending email messages back to the computer that originated the suspected spam