Explanation:
In case of default by joint promisors, the promisee has the right to sue any one of the joint promisors for the entire promised amount. This is because a joint promise is a contract in which two or more persons make a promise to the same promisee to perform the same obligation. The promise of each promisor is co-extensive with the promise of every other promisor, and they are jointly and severally liable.

However, there are certain limitations to this right of the promisee. The limitations are discussed below:

Cannot sue any single promisee:
The promisee cannot sue any single promisor for the entire promised amount because the promise of each promisor is co-extensive with the promise of every other promisor. Therefore, the promisee has to sue all the joint promisors together for the entire promised amount.

Can sue any one of them to the extent of his share in the joint promise:
If the promisee cannot sue all the joint promisors together for the entire promised amount, he can sue any one of them to the extent of his share in the joint promise. This means that the promisee can recover from each promisor only the proportion of the promised amount for which he is liable.

Can sue any one of them for the entire promise:
If the promisee has already recovered a proportionate amount from one of the joint promisors, he can still sue any one of them for the entire promised amount. However, the promisor from whom the promisee has already recovered a proportionate amount will have the right to claim contribution from the other promisors for their share in the joint promise.

Conclusion:
Therefore, in case of default by joint promisors, the promisee has the right to sue any one of them for the entire promised amount, but he cannot sue any single promisor for the entire promised amount. The promisee can recover from each promisor only the proportion of the promised amount for which he is liable.

According to section 43 of Indian Contract Act,1872
"When any two or more persons has made a joint promise to a promisee and the promisee ,in contrary to the contract, can ask any one or more joint promisors for the entire performance. However, the promisor or promisors who is compelled for the entire performance can claim contribution from other joint promisors"