A trustee may be discharged from his office only as follows:—
(a)by the extinction of the trust;
(b)by the completion of his duties under the trust;
(c)by such means as may be prescribed by the instrument of trust;
(d)by appointment under this Act of a new trustee in his place;
(e)by consent of himself and the beneficiary, or, where there are more beneficiaries than one, all the beneficiaries being competent to contract; or
(f)by the Court to which a petition for his discharge is presented under this Act.