context: In 1899, Joseph Kolaizcek, the grandfather of Oskar Matzerath, the main character, is being pursued by the police through rural Kashubia. He hides underneath the skirts of a young woman named Anna Bronski, with whom he later has a daughterÂ â Oskar's mother. He evades the authorities for a year, but when they find him again, he either drowns or escapes to America and becomes a millionaire.
  Anna's daughter Agnes has two lovers: her cousin Jan Bronski, a Polish Post Office worker, and Alfred Matzerath, whom she marries. The two men are great friends. Agnes gives birth to a son, Oskar. Oskar's father is uncertain; Oskar himself believes he is Jan's son.
  On Oskar's third birthday, he is given a tin drum. He decides to stop growing and throws himself down the cellar stairs. From that day on, he does not grow at all. Oskar discovers that he can shatter glass with his voice, an ability he often uses whenever he is upset. Oskar's drumming also causes the members of a Nazi rally to start dancing. During a visit to the circus, Oskar meets Bebra, a performing dwarf to whom he can relate.
  When Alfred, Agnes, Jan and Oskar are on an outing to the beach, they see an eel-picker collecting eels from a horse's head used as bait. The sight makes Agnes vomit repeatedly. Alfred buys some of the eels and prepares them for dinner that night. When he insists that Agnes eat them, she becomes distraught and retreats to the bedroom. Jan enters and comforts her, all within earshot of Oskar who is hiding in the closet. She calmly returns to the dinner table and eats the eels. Over the next few days, she binges on fish. Anna Bronski helps reveal that Agnes is worried her pregnancy is due to her relations with Jan. In anger, Agnes vows that the child will never be born. She dies, though the cause is never revealed. At the funeral, Oskar encounters Sigismund Markus, the kindly Jewish toy seller who supplies him with replacement drums, and who was also in love with Agnes. Markus is ordered by two of the mourners to leave because he is Jewish; Nazism is on the rise, and the Jewish and Polish residents of Danzig (GdaÅsk) are under increasing pressure. Markus later commits suicide after his shop is vandalized and a synagogue is burned down by SA men.
  On 1 September 1939, Oskar and Jan go looking for Kobyella, who can repair his drum. Jan slips into the Polish Post Office, despite a Nazi cordon, and participates in an armed standoff against the Nazis. During the ensuing battle, Kobyella is fatally shot and Jan is wounded. They play Skat until Kobyella dies and the Germans capture the building. Oskar is taken home, while Jan is arrested and later executed.
  Alfred hires sixteen-year-old Maria to work in his shop. Oskar seduces Maria, but later discovers Alfred having sex with her. Oskar busts into the room, causing Maria to become angry at Alfred. She and Oskar fight, and he hits her in the stomach. She later gives birth to a son, who Oskar is convinced is his. Oskar also has a brief sexual relationship with Lina Greff, the wife of the local grocer and scoutmaster.
  During World War II, Oskar meets Bebra and Roswitha, another dwarf performer in Bebra's successful troupe. Oskar decides to join them, using his glass-shattering voice as part of the act. Oskar and Roswitha have an affair, but she is killed by artillery fire during the Allied invasion of Normandy while on tour.
  Oskar returns home. Much of the city has been destroyed and the Russians are fast approaching. Oskar gives Maria's three-year-old son Kurt a tin drum like his own. The Russians break into the cellar where the family is hiding. Some of them gang-rape Lina. Alfred is killed by an Asiatic soldier after swallowing and choking violently on his Nazi party pin, apparently betrayed by Oskar.
  During Alfred's burial, Oskar decides to grow up, and throws his drum into the grave. As he does, Kurt throws a stone at his head and he falls into the grave. Afterward, an attendee announces Oskar is growing again. The family, apart from Anna Bronski, leave for the West.
question: Who is Maria's son?
answer: Kurt