Answer: b. It is unicellular.
Step-by-step explanation:
Amoeba is unicellular eukaryotic organism. It lives in freshwater or saline water habitat. Mostly the animals are multicellular in nature. The multicellular nature supports various functions such as respiration, digestion, excretion and others. Amoeba is a simple organism in which such complex functions does not occur. Hence, it is not an animal.