Answer:
C) manatee
Explanation:
According to Wikipedia, "Cetaceans are aquatic mammals constituting the infraorder Cetacea. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet."
The most important thing to note here is the part saying "exclusively carnivorous diet." Manatees are aquatic mammals with a fully aquatic lifestyle and large size, but they are not carnivorous. Manatees feed on water grasses, weeds, and algae, according to National Geographic. So, manatees are not cetaceans.
Hopefully that was helpful! :)
