Explanation:

When it comes to time-barred debt, it refers to a debt that is past the statute of limitations, which means the creditor can no longer sue the debtor in order to collect the debt. In such cases, the debtor is not legally obligated to repay the debt. However, there are certain circumstances in which a debtor may choose to voluntarily repay a time-barred debt. In order for this repayment to be enforceable, it must meet specific requirements.

Requirement for a promise to pay time-barred debt:

In the given options, the correct answer is option 'C', which states that a promise to pay a time-barred debt must be in writing and signed by the debtor or his authorized agent. This requirement is based on the principle of contract law, which states that any promise to pay a time-barred debt must be supported by consideration and must be in writing to be enforceable.

Reasons for requiring a written promise:

1. Clarity and Documentation: A written promise provides clear evidence of the debtor's intention to repay the debt. It ensures that both parties understand the terms of the repayment agreement and helps to avoid any misunderstandings or disputes in the future.

2. Protection for the Debtor: Requiring a written promise helps protect the debtor from potential fraudulent claims or attempts to collect on a time-barred debt. It ensures that the debtor has a record of the agreement, which can be used as evidence in case the creditor tries to pursue legal action.

3. Enforceability: A written promise to pay a time-barred debt is more likely to be enforceable in court than an oral promise or an implied promise. It provides a stronger legal basis for the creditor to seek repayment if the debtor fails to uphold the agreement.

Conclusion:

In conclusion, a promise to pay a time-barred debt must be in writing and signed by the debtor or his authorized agent in order to be enforceable. This requirement ensures clarity, documentation, and enforceability in the repayment agreement and protects both parties involved.