Step 1: Understanding Section 43 of the Indian Contract Act.
Section 43 of the Indian Contract Act provides that when two or more persons promise to perform an obligation, and one of them becomes untraceable, the remaining parties are still liable to perform the obligation. Therefore, A can compel Z to pay the full amount.
Step 2: Explanation of the options.
- (a) A can, under Section 43 para 1: This is correct, as per the provisions of the Indian Contract Act, A can compel Z to pay the full amount.
- (b) A can under Section 49 para 1: This is incorrect, as Section 49 does not apply to this situation.
- (c) A cannot and will have to wait till X, Y become traceable: This is incorrect. A does not have to wait for X and Y to become traceable.
- (d) Z can be compelled only for one third: This is incorrect. Z is liable for the full amount, not just one-third.
Step 3: Conclusion.
Thus, the correct answer is (a) A can, under Section 43 para 1.