One study showed that participants were first involved in learning to eliminate prejudice, and the subjects were played with the sounds associated with the elimination of that prejudice learning, and then subjects were put into a deep sleep while repeating those related plays. The linked voice has reactivated learning to eliminate this prejudice. It was found that the prejudice was significantly reduced compared to before sleep, and the higher the quality of sleep, the more the prejudice was reduced. The researchers speculated that sleep intervention can reduce social prejudice and discrimination. Which of the following, if true, would best support the above argument? ['It is difficult for ordinary people to get sleep interventions to eliminate biased learning.', 'People who sleep well and sleep well are less likely to develop prejudice and discrimination than others.', 'Discrimination in height is significantly reduced after sleep intervention.', 'Some of the subjects receiving sleep interventions were not significantly prejudiced or discriminated against.']