Final answer:
Hadrosaurids may have been the only b) aquatic dinosaurs, as they had adaptations for an aquatic lifestyle.
Step-by-step explanation:
Hadrosaurids may have been the only aquatic dinosaurs. While most dinosaurs were terrestrial, there is evidence to suggest that some hadrosaurids had adaptations for an aquatic lifestyle. Their broad, paddle-like tails and webbed feet indicate that they may have been well-suited for swimming and living in water habitats.