Concept:Soda water gets its fizz from dissolved carbon dioxide gas under pressure, which creates carbonated water.Explanation:When carbon dioxide (CO2​) gas is forced into water at high pressure, it dissolves and forms carbonic acid, giving the drink its bubbles and slight tang. Other gases like carbon monoxide (poisonous), oxygen (not soluble enough), or marsh gas (methane, flammable) are not used.Answer:B. Carbon dioxide