Hyman Kaplan: Hyman Kaplan is a character from the book "The Education of H_Y_M_A_N K_A_P_L_A*N" by Leo Rosten. He is a Jewish immigrant who attends night school to learn English, making this the correct answer.
Sadao: Sadao is a character from the short story "The Enemy" by Pearl S. Buck. He is a Japanese doctor who does not attend night school to learn English. Therefore, this option is incorrect.
Tom Benecke: Tom Benecke is a character from the short story "Contents of the Dead Man's Pocket" by Jack Finney. He is a young man working in an office and does not attend night school to learn English. Thus, this option is incorrect.
Dagmar: Dagmar is a character from the novel "I Remember Mama" by Kathryn Forbes. She is a young girl in a Norwegian immigrant family, and there is no indication that she attends night school to learn English. Hence, this option is incorrect.