## Core Concept
Vitamin A deficiency is a significant public health problem in many developing countries, leading to night blindness, weakened immune systems, and increased mortality. Prevention involves dietary improvements, fortification of foods, and supplementation. Supplements are particularly crucial for high-risk groups such as pregnant women, lactating mothers, and young children.

## Why the Correct Answer is Right
The correct approach to preventing vitamin A deficiency through supplements involves understanding the target groups and the frequency of administration. Typically, vitamin A supplements are given to children aged 6–59 months, pregnant women, and breastfeeding mothers. The World Health Organization recommends that children receive vitamin A supplements every 6 months in areas where vitamin A deficiency is a public health problem.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is not provided, so we cannot assess its accuracy directly.
- **Option B:** Similarly, without the content of Option B, we cannot evaluate its correctness.
- **Option C:** Without details on Option C, we cannot determine why it might be incorrect.
- **Option D:** This option is stated as the correct answer but without context, we must infer based on standard practices.

## Clinical Pearl / High-Yield Fact
A critical point to remember is that vitamin A supplementation is a strategy used primarily for children aged 6–59 months and certain vulnerable groups like pregnant and lactating women. The typical dose for children is 100,000 IU for those aged 6–11 months and 200,000 IU for those aged 1–5 years, given every 6 months. This strategy aims to reduce mortality and morbidity associated with vitamin A deficiency.

## Correct Answer: D.