51.
The answer is: C
Explanation
The correct option is C: Both (a) & (b).
In relation to devolution of joint liabilities, as a general rule the Indian Contract Act incorporates the principle of both survivorship and succession. This means that when two or more persons have made a joint promise, then, unless a contrary intention appears by the contract, all such persons, during their joint lives, and, after the death of any of them, his representative jointly with the survivor or survivors, and, after the death of the last survivor, the representatives of all jointly, must fulfil the promise.
This principle is stated in Section 42 of the Indian Contract Act, 1872. It ensures that the joint liability of the promisors is not affected by the death of any of them, and that the promisee or his heirs can claim performance from the surviving or the representative promisors.