Task: Question Answering
Input (English): When a mixture of oxygen and hydrogen is ignited in a test tube, the reaction shown occurs. Hydrogen + Oxygen -> Water + Energy What happens to the total mass of the contents of the test tube?  
 (A) The total mass increases. (B) The total mass decreases. (C) The total mass remains the same. (D) Part of the mass is changed to heat energy.
Output (English): C