**Core Concept**
The Recommended Dietary Allowance (RDA) represents the average daily nutrient intake level sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy individuals in a particular life stage and gender group. The RDA is based on the estimated average requirement (EAR) plus an additional 2 standard deviations to account for individual variability.

**Why the Correct Answer is Right**
The RDA is designed to provide a margin of safety above the estimated average requirement (EAR), which is the average daily nutrient intake level estimated to meet the nutrient requirements of half the healthy individuals in a particular life stage and gender group. The 2 standard deviations added to the EAR are intended to cover 97-98% of the population, ensuring that the RDA meets the nutrient needs of nearly all healthy individuals.

**Why Each Wrong Option is Incorrect**

* **Option A:** This option underestimates the RDA's intended coverage, as it would only account for 50% of the population.
* **Option B:** This option also underestimates the RDA's intended coverage, as it would only account for 75% of the population, leaving 25% without adequate nutrient intake.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the RDA is not the same as the Adequate Intake (AI), which is used when there is not enough evidence to establish an EAR. The AI is a recommended intake value based on observed or experimentally determined estimates of nutrient intake by a group (or groups) of healthy people.

**✓ Correct Answer: C. 98% of individuals**