In the impression that biofuel is a renewable green energy source, and the latest published research results have subverted this traditional impression. Researchers have found that biofuel may be converted into acetaldehyde due to its incomplete combustion. In addition, it pollutes the air, and this pollution will cause 1,400 premature deaths each year in country M. Therefore, some medical institutions in country M believe that the promotion of biofuels should be suspended at this stage to limit their use. Which of the following, if true, would raise the most powerful questions about the opinions of medical staff. ['At this stage, scientists from country M have developed new technologies to fully burn biofuels.', 'Pollution of other fuels currently being used in country M causes more than 3,000 premature deaths each year.', 'Traditional fuels such as petroleum have been improved in technology, and the pollution caused by combustion has been greatly reduced.', 'Scientists predict that with the advancement of research work, new biofuels will not produce acetaldehyde in 5 years.']