Answer:
It is likely a protist, due to the presence of the tail-like structure (flagellum).
Step-by-step explanation:
Protist just means any eukaryotic cell that is not a animal, plant, or fungus.
This is tricky because some fungi are unicellular (yeasts) and might only be distinguished from protists via their evolutionary history (all fungi are more related to animals than they are to any protist).
One difference between the two though is that most protists are unicellular and have flagella, and most types of fungi do not.