Generate a question that has the following answer: Dong-Jin for the following movie plot: Ryu is a deaf-mute man working in a factory. His ailing sister is in desperate need of a kidney transplant, but Ryu's is not a match. After he is laid off from his job, Ryu takes his severance money and contacts a black market organ dealer to exchange one of his kidneys for one that his sister can use. The dealers disappear after taking Ryu's kidney and money. Three weeks later, Ryu learns from his doctor that a donor has been found, but he is unable to afford the operation. To raise money for the operation, Yeong-mi, Ryu's radical anarchist girlfriend, suggests kidnapping the daughter of an executive that fired Ryu. They kidnap Yu-sun, the young daughter of Dong-jin. The girl stays with Ryu's sister, who believes Ryu is merely babysitting her. Ryu and Yeong-mi successfully collect the ransom from Dong-jin. However, Ryu's sister discovers the plan and commits suicide to stop being a burden to him. Ryu takes Yu-sun and his sister's body to a suburban riverbed they used to frequent as children, and begins to bury her. Distracted by the burial and unable to hear, Ryu is unaware when Yu-sun slips into the river, and she drowns. As Dong-jin mourns his daughter, he hires an investigator to find her kidnappers. Dong-jin finds Yeong-mi and tortures her. She apologizes for Yu-sun's death, but warns Dong-jin that her friends (a terrorist group) will kill him if she dies. Unfazed by the threats, Dong-jin electrocutes her. Meanwhile, Ryu locates and murders the organ dealers. He returns to Yeong-mi's apartment and sees the police removing her corpse. Ryu and Dong-jin wait at each other's residence in an attempt to kill the other. Ryu, the first to return home, is knocked unconscious by Dong-jin's booby trap. Dong-jin takes Ryu to the riverbed where his daughter died, slashes his Achilles tendons and waits for Ryu to bleed to death. After dismembering Ryu's corpse, Dong-jin begins digging a hole, when a group of men arrive. After surrounding and stabbing Dong-jin, one man pins a note to his chest with a knife. The note...
The answer to this question is:
From whom did Ruy and Yeong-mi collect the ransom?