Concept:Water gas is a fuel gas mixture obtained by passing steam over red-hot coke. It is also called synthesis gas because it is used in the production of methanol and other chemicals. Its main components are carbon(II) oxide and hydrogen.Explanation:The reaction for the gasification of coke is: C(s)+H2O(g)red heatCO(g)+H2(g) Here, carbon(II) oxide (CO) and hydrogen (H2) are produced in the form of water gas. Water gas does not contain nitrogen (N2) because the process avoids air. It also does not contain carbon(IV) oxide (CO2) as a principal product. Thus, the two gases that make up water gas are exactly hydrogen and carbon(II) oxide.Answer:C. Hydrogen and Carbon(II) oxide.