Baker’s yeast is?
A) S. cerevisiae
B) S. ludwigii
C) S. octosporus
D) Schizosaccharomyces

Hint:-Yeasts are organisms that come under the fungi kingdom. They are unicellular and their cell organelles are not bound by any membrane (eukaryotic cells). They usually undergo asexual mode of reproduction, in most cases it is budding. Schizosaccharomyces reproduce by binary fission. Some of these organisms are able to grow in anaerobic conditions and can partake in the fermentation process.

Complete Answer:-Baker’s yeast as the name suggests is the yeast that is used to make bread. These yeasts act as biological leavening agents. Leavening agents are certain ingredients added to the batter or the dough to facilitate the fermentation process. A leavening agent ferments the sugar present in the batter to produce gas i.e. carbon dioxide. This causes the dough to rise up.
Saccharomyces cerevisiae are yeast cells that take part in the fermentation processes that occur while making wine and bread. Certain strains of S. cerevisiae are known as baker’s yeast.Saccharomycodes ludwigii are yeast cells that contaminate the stored wine. The organism can survive at high ethanol concentrations and produce ethyl alcohol or acetic acid. This is undesirable and results in spoilage of wine.
S. octosporus is one of the four species that belong to the Schizosaccharomyces genus. This species as well as the other three species are studied to understand the evolution of the eukaryotic cells.
The correct option is (A).

Note:- Certain strains of Saccharomyces cerevisiae are called brewer’s yeast. They partake in the winemaking process. The most important distinction between the baker’s yeast and brewer’s yeast is that the former is most concerned with carbon dioxide gas production. While in the case of winemaking, the brewer’s yeast ferments sugar to produce both carbon dioxide as well as alcohol (ethanol).