Which of these containers is used to store, transport, and serve beer?

A keg is a small cask used for storing liquids. It is commonly used to store, transport, and serve beer. Beer kegs are made of stainless steel, or less commonly, of aluminium. Beer kegs are designed to maintain the carbonation in a beverage by storing it with pressurized carbon dioxide in the headspace above the liquid. Other alcoholic or non-alcoholic drinks, carbonated or non-carbonated, may be housed in a keg as well.

Source: Wikipedia