In municipal finance, a necessary requirement for executing a refunding plan is:

A detailed refunding plan submission is essential for executing a refunding plan because it outlines the strategy for replacing an existing bond issue with a new one. This plan typically details the financial rationale, including the projected savings in interest costs, the timing of the refunding, and how the new bonds will be structured.

Moreover, a comprehensive refunding plan is a key tool for ensuring that the refunding process adheres to legal and financial regulations and serves the best interests of the municipality and its stakeholders. It also reassures bondholders and investors of the validity of the process.

While the other options might touch on aspects related to bond management or legislative action, they are not fundamental requirements for initiating a refunding plan. For instance, immediate repayment of all existing bonds does not align with the nature of refunding, which aims to restructure rather than outright eliminate debt. Similarly, obtaining approval from all bondholders is impractical, as not all might need to be consulted at the same level. Lastly, new legislation on interest computation might be necessary in certain scenarios but is not a strict prerequisite for a refunding plan itself.