Which of the given situations is the MOST unlikely to allow for data recovery?

Using strong magnetic fields to erase a drive, known as degaussing, is the least probable method to result in recoverable data. In most cases, deleted files can be retrieved as only the file index information is eliminated until that space is required and overwritten. Quick formats operate in a similar fashion, leaving residual data, and any files overwritten by smaller ones will leave behind fragments of data that can be retrieved and analyzed.