Answer:
A. adequacy
Explanation:
Nutritional adequacy can be defined as the intake or consumption of adequate and sufficient amounts essential nutrients that is required to fulfill the recommended needs to achieve optimal health. Nutritional adequacy is dependent on the recommended nutrient requirement and nutrient intake necessary for a certain population or individual.
In the case of Jack, his recommended daily nutrient intake for optimal health, based on his energy need is 2,800 kilocaries, but he consumes half of recommended daily nutrient intake, this means his diet is lacking of nutritional adequacy.