Task: Question Answering
Input (English): During a lab investigation, students were asked to determine the best way to clean up an oil spill using different materials. Investigation Materials • filter paper • foam sponge • metal wire screen • thin sock filled with hair The students tested the materials by placing each material into separate buckets containing oil and water. They recorded their observations on which material absorbed the most oil. Why would the students' teacher ask them to repeat their tests?  
 (A) to determine if water and oil can be separated (B) to learn more about how to protect wildlife during an oil spill (C) to improve the chances of obtaining accurate oil cleanup results (D) to increase the total amount of oil removed from each container
Output (English): C