When there is insufficient research to determine the rda for a nutrient, the based on estimates of intakes that appear to maintain a defined nutritional state in a specific life stage, is the nutrient standard. daily value (dv) adequate intake (ai) estimated average requirement (ear) tolerable upper intake level (ul)?

Option B, Adequate Intake (AI)

Explanation:

When the RDA research is inadequate or by any means the RDA cannot be determined for any nutrient, then the adequate intake value is preferred.

Adequate intake value is defined as the average level of nutrient (belonging to a particular group) that must be taken depending upon observed values or approximations deduced through experiments for apparently healthy people.

Hence, option B is correct