For many types of crops, hybrid strains have been developed that have been found in test plantings to produce significantly higher yields than were produced by traditional nonhybrid strains of those crops planted alongside them. However, in many parts of the world where farmers have abandoned traditional nonhybrid strains in favor of the hybrid strains, crop yields have not increased. Which one of the following, if true, most helps to resolve the apparent discrepancy? ['Most farmers who plant the hybrid strains of their crops have larger farms than do farmers who continue to plant traditional nonhybrid strains of the same crops.', 'Hybrid strains of crops produced higher yields in some areas than did nonhybrid strains in those areas.', 'Many governments subsidize farmers who plant only hybrid strains of staple crops.', 'The hybrid strains were tested under significantly better farming conditions than are found in most areas where farmers grow those strains.']