Which among the following is not a prokaryote?

An organism that does not possess a true nucleus (nucleus with nuclear membrane) and membrane-bounded organelles are called as prokaryotes. Monerans are prokaryotes. Eg. bacteria (Mycobacterium), cyanobacteria (Nostoc and Oscillatoria). Saccharomyces belong to Kingdom Fungi which possess a true nucleus and membrane-bounded organelles i.e., eukaryotic. Thus, the correct answer is Saccharomyces.