Which of the following refers to the irrevocable form of Talaq?

Talaq-ul-Biddat is the irrevocable form of talaq (divorce) under Muslim law. It is an innovative form not recognized by the Prophet but introduced later. It becomes effective immediately upon pronouncement and cannot be revoked. In contrast, Talaq-ul-Ahsan and Talaq-ul-Hasan are approved forms that remain revocable during the iddat period (waiting period). Talaq-i-Tafweez refers to delegated divorce where the husband delegates his power of divorce to his wife.