Final answer:
Painful behavior in a rabbit is characterized by an animal not moving with its back arched.
Step-by-step explanation:
Painful behavior in a rabbit is characterized by an animal who is not moving with its back arched. This posture is commonly seen in rabbits that are in pain or discomfort. When a rabbit is experiencing pain, it may become immobile and stiff, with its back arched. When a rabbit exhibits painful behavior, it may show signs that are not necessarily typical for a healthy and comfortable animal. Among the listed behaviors, not moving with its arched back is indicative of pain or discomfort in rabbits. In contrast, behaviors such as grooming, eating, producing fecal balls, and hopping in its cage are more often associated with normal, healthy rabbit activities. A rabbit may arch its back and remain motionless due to a variety of potential causes, such as gastrointestinal discomfort, musculoskeletal pain, or other underlying health issues. Therefore, option d) 'Not moving with its back arched' is the correct answer to this question.