A Mac ROM. For B2, you must extract a ROM file from an old 68K Mac that you own. Use CopyROM or ROM-grabber for the extraction. For SheepShaver, use the Mac OS ROM Update 1.0, provided by Apple. None of the other Apple-distributed software-based New World ROMs, nor the Old World ROMs I've extracted from my own Macs have worked. However, to use this ROM, I think you'll need at least System 8.5 (I couldn't get it to run on OS 8.1; maybe older systems don't support New World ROMs?). Extract the ROM from the updater with TomeView. These extractors are themselves Classic apps, so you'll need access to a Mac capable of running Classic or older to get the ROMs.