According to Section 29 of the Indian Partnership Act, 1932, a partner has the right to transfer his interest in the firm by various means. These means include sale, charge, and mortgage. Therefore, the correct answer is option 'D' - all of these.


The Indian Partnership Act, 1932 governs the transfer of a partner's interest in a partnership firm. This act provides for the various ways in which a partner can transfer his interest in the firm.


A partner can transfer his interest in the firm by way of sale. This means that the partner can sell his share or interest in the partnership firm to another person. The sale can be made for a consideration, and the transferee becomes a partner in the firm in place of the transferor.


A partner can also transfer his interest in the firm by way of charge. This means that the partner can create a charge on his share or interest in the partnership firm in favor of another person. The charge can be created to secure a debt or obligation, and the transferee of the charge does not become a partner in the firm.


Additionally, a partner can transfer his interest in the firm by way of mortgage. This means that the partner can mortgage his share or interest in the partnership firm as security for a loan or debt. The mortgagee does not become a partner in the firm but has the right to sell the mortgaged interest in case of default.


In conclusion, as per Section 29 of the Indian Partnership Act, 1932, a partner can transfer his interest in the firm by sale, charge, or mortgage. These methods provide different ways for a partner to transfer his share or interest in the partnership firm. It is important to comply with the provisions of the Partnership Act and any relevant partnership agreement while effecting such transfers.