in accordance with a contract between the existing partners or with the consent of all the existing partners
in accordance with a contract between the existing partners or with the consent of all the existing partners subject to the provisions of Section 30 of the Act
after obtaining specific approval of the Registrar of Firms and Societies, to this effect
Admitting a new partner requires either an existing partnership agreement OR unanimous consent of all current partners, subject to Section 30 restrictions. Section 30 specifically addresses admission of new partners. Mere consent of the new person (D) or registrar approval (C) is not the legal requirement.