Which of these is a unicellular fungi?

Answer: Option A

Saccharomyces is a unicellular fungus.
Saccharomyces is a genus of fungi that includes many species of yeasts. They are unicellular and saprotrophic fungi.
Saccharomyces cerevisiae, also known as baker's yeast, is a unicellular fungus that is used to make bread and other wheat-based products.