The reaction given in the question involves the formation of carbon monoxide (CO) and hydrogen gas (H2) from methane gas (CH4) and water vapor (H2O). The mixture of CO and H2 produced in this reaction is commonly known as water gas.

Option 1: Natural gas. Natural gas primarily consists of methane (CH4), but it does not undergo the same reaction as mentioned in the question. Therefore, option 1 is incorrect.

Option 2: Water gas. Water gas is the correct answer. It is produced by reacting methane and water vapor at high temperatures. This mixture of CO and H2 is often used as a fuel source in various industrial processes.

Option 3: Producer gas. Producer gas is a different mixture of gases produced by burning coal or biomass with a limited amount of oxygen. It contains carbon monoxide, hydrogen, nitrogen, and small amounts of other gases. It is not formed by the reaction stated in the question, so option 3 is incorrect.

Option 4: Industrial gas. "Industrial gas" is a broad term that can refer to various gases used in industrial processes. While water gas can be considered a type of industrial gas, option 4 is too general and does not specifically refer to the