Correct Answer: 

The correct answer is B: Fungi.

Explanation of Options:

Option A: Protista  
 • Incorrect. Yeast does not belong to the Protista group.
 • Protista is a diverse group of eukaryotic microorganisms, which includes organisms like algae and protozoa.
 • Yeast is a eukaryotic organism but is classified under a different kingdom.
 • Protists are generally unicellular, whereas yeast, although unicellular, is classified based on its fungal characteristics.

Option B: Fungi  
 • Correct. Yeast belongs to the Fungi group.
 • Fungi are a kingdom of usually multicellular eukaryotic organisms that are heterotrophic and have cell walls made of chitin.
 • Yeast is a type of fungus that is unicellular and is used in baking and brewing due to its fermentation abilities.
 • Yeast reproduces asexually by budding, a characteristic feature of many fungi.

Option C: Monera  
 • Incorrect. Yeast does not belong to the Monera group.
 • Monera is an outdated classification that included prokaryotic organisms like bacteria.
 • Yeast is a eukaryotic organism, meaning it has a defined nucleus and organelles, unlike prokaryotic organisms.
 • The Monera classification is no longer used in modern taxonomy, as it has been replaced by the domains Bacteria and Archaea.

Option D: Protozoa  
 • Incorrect. Yeast does not belong to the Protozoa group.
 • Protozoa are a subset of Protista, consisting of single-celled eukaryotes that are often motile.
 • Yeast is non-motile and does not exhibit the characteristics typical of protozoa, such as movement via cilia or flagella.
 • Protozoa are primarily heterotrophic, but their classification is based on their motility and other factors, not on their ability to ferment sugars like yeast.