Final answer:
A healthy person requires energy intake ranging from 1,300 to 3,000 kcal per day. To gain or lose 1 pound per week, a healthy person would need to change their energy intake by approximately 500 kcal per day.
Step-by-step explanation:
A healthy person requires energy intake ranging from 1,300 to 3,000 kcal per day depending on their activity level.
To gain or lose 1 pound per week, a healthy person would need to change their energy intake by approximately 500 kcal per day.
Therefore, the correct answer is a) 500 kcal/day.