Answer:
c. Density.
Explanation:
The principle of nutrient used here is Density. Here the person had two options either he could choose chicken leg or 2 tablespoon of peanut butter both provide 0.5 milligram of iron.
But since he wanted less calorie intake he chooses chicken leg as the calorie intake from peanut butter was almost twice from butter than from the chicken. Â hence option is correct.