Which among the following is not a prokaryote?

Among the given options, Saccharomyces is the scientific name of yeast belongs to kingdom Fungi, i.e. it is a eukaryote. They possess a well-defined nucleus and other cell organelles. Nostoc and Oscillatoria are cyanobacteria, while Mycobacterium is a true bacterium. Cyanobacteria and bacteria both are prokaryotes as they lack a well-defined nucleus and other cell organelles. They belong to the kingdom Monera.