A reporter wants to investigate the reasons for the high levels of air pollution in a locality. Initial research reveals two possible sources: an old thermal power plant and a sheet metal factory. She hands out the questionnaire above to the local residents to investigate the matter further. What can be concluded about the results of her investigation? A) It would help to get to the root cause of the air pollution in the locality. B) It would help her take people's opinions and shut down both the sources of pollution. C) It would be biased because no questions about the sheet metal factory have been asked. D) It would be inconclusive because there are no questions about the nature of the pollutants.