Indian Contract Act, 1872
The performance of any promise may be made in any manner, or at any time which the promisee prescribes or sanctions.
(a) B owes A 2,000 rupees. A desires B to pay the amount to A's account with C, a banker. B who also banks with C, orders the amount to be transferred from his account to A's credit and this is done by C. Afterwards, and before A knows of the transfer, C fails. There has been a good payment by B.
(b) A and B are mutually indebted. A and B settle and account by setting off one item against another, and B pays A the balance found to be due from him upon such settlement. This amounts to a payment by A and B, respectively, of the sums which they owed to each other.
(c) A owes B 2,000 rupees. B accepts some of A's goods in deduction of the debt. The delivery of the goods operates as a part payment.
(d) A desires B, who owes him Rs. 100, to send him a note for Rs. 100 by post. The debt is discharged as soon as B puts into the post a letter containing the note duly addressed to A.