In the play A Dollhouse Whose signature does Nora forge?

In the play "A Doll's House" by Henrik Ibsen, Nora forges her father's signature. She does this to secure a loan that she believes is necessary to save her husband, Torvald, from illness. This act of forgery becomes a pivotal point in the story, as it ultimately leads to the unraveling of her marriage and her quest for independence.