The most appropriate option for teens who should use a low-calorie eating plan to lose weight is:
c. Teens who are seriously overweight and in the care of a medical professional.
This choice emphasizes the importance of medical supervision when it comes to weight loss for teens, particularly for those who are seriously overweight, as it ensures that the plan is safe and tailored to their individual health needs.
Options a, b, and d may not be appropriate reasons for a low-calorie eating plan, as they may reflect personal or societal pressures rather than medical necessity.