Task: Question Understanding
Input (English): Question: A factory owner wants to be sure that he does not pollute the air during the manufacturing process. What is a good way to make sure he is not polluting the air? (A) Recycle the water used during the manufacturing process. (B) Swab the machines to test for any oily residues. (C) Test samples of smoke coming from the factory's smokestacks. (D) Use only bottled water in the manufacturing process.?
Output (English): pollute, air, manufacturing, polluting