Amanda needs to notify yasmin that the proposal she wrote did not get funded. which communication channel is most appropriate

In this case, it can be inferred that Amanda either reports to Yasmin or is a coworker of Yasmin in the same team. For this sort of situation, it is most appropriate that Amanda uses a formal mode of communication to report that the proposal did not get funded. With this situation, either an email has to be sent including the reasons as to why the proposal did not get accepted. Amanda may also call a meeting with Yasmin in order to discuss what happened to the proposal and why it did not get funding. 

Absolute