Which of the answers below does ATV stand for?

An all-terrain vehicle (ATV), also known as a quad, quad bike, three-wheeler, four-wheeler or quadricycle as defined by the American National Standards Institute (ANSI) is a vehicle that travels on low-pressure tires, with a seat that is straddled by the operator, along with handlebars for steering control. As the name implies, it is designed to handle a wider variety of terrain than most other vehicles. Although it is a street-legal vehicle in some countries, it is not street-legal within the states of Australia, the United States or provinces of Canada.

The current ANSI definition, ATVs are intended for use by a single operator, although some companies have developed ATVs intended for use by the operator and one passenger. The passenger is not required to have a helmet. These ATVs are referred to as tandem ATVs.The rider sits on and operates these vehicles like a motorcycle, but the extra wheels give more stability at slower speeds. Although most are equipped with three or four wheels, six-wheel models exist for specialized applications.