Which character is rejected by Dunny for trying to take on a maternal role?

The character who is rejected by Dunny for attempting to take on a maternal role is indeed Diana. In "Fifth Business," Diana is portrayed as someone who wants to provide comfort and care, embodying a nurturing aspect that can be seen as maternal. However, Dunny has complex feelings about his past and is particularly resistant to traditional maternal figures due to the impact of his own upbringing and the figures of women in his life, specifically Mrs. Dempster. His rejection of Diana underscores his struggle with intimacy and vulnerability, as he grapples with his identity and the influence of the women who have impacted his life.

While Leola and Liesl do have significant roles in Dunny's life, their interactions do not emphasize a maternal aspect in the same way that Diana's attempts do. Leola's relationship with Dunny is more romantic and complicated, while Liesl represents a different kind of allure and complexity. Mrs. Dempster, on the other hand, is deeply tied to Dunny's childhood and his sense of duty, but he does not reject her in the same direct manner as he does with Diana, who desires to step in to fulfill that nurturing role. This makes Diana the correct choice for this question.