Answer: D. Chytridiomycota
Step-by-step explanation:
Based on the observed characteristics of chitin in the cell walls and flagellated spores, the newly discovered fungus is most likely a member of the Chytridiomycota group. Chytridiomycota is a group of fungi that are characterized by having chitin in their cell walls and flagellated spores, which are unique among fungi. The other three groups of fungi mentioned in the question, Zygomycota, Basidiomycota, and Ascomycota, do not have flagellated spores. Zygomycota have non-flagellated spores, while Basidiomycota and Ascomycota have spores that are produced externally on specialized structures. Therefore, based on the observed characteristics, the newly discovered fungus is most likely a member of the Chytridiomycota group.