context: The Korean Graduate Employee Union is a labor organization established in December 2017 to respond to graduate student human rights violations and exploitation of labor rights. Korea's first graduate student union. The official name of the KCTU is the branch of the National Graduate Student Union and the abbreviation is Graduate Student Union. The superior body is under the Democratic Union.
question: What is the main task of graduate student unions?
answers.text: respond to graduate student human rights violations and exploitation of labor rights