Illegal. According to the query of the Criminal Law of People's Republic of China (PRC), selling 3900 education cards with a Ji Zhang score of 100 belongs to fraud or pyramid schemes. Fraud refers to the act of defrauding a large amount of public and private property by fabricating facts or concealing the truth for the purpose of illegal possession. MLM refers to the behavior of organizers to develop personnel, through the development of personnel or on the condition of paying a certain fee, asking the developed personnel to obtain the qualification to join, and illegally obtaining wealth.