## **Core Concept**
The question pertains to the standard composition of tablets used for iron and folic acid supplementation in adults. These supplements are crucial for preventing and treating iron deficiency anemia and folate deficiency, particularly in pregnant women and individuals with specific nutritional needs.

## **Why the Correct Answer is Right**
The correct answer, **B. 100 mg of elemental iron and 500 mcg of folic acid**, reflects the typical composition of such supplements. The amount of elemental iron is significant because it directly correlates with the bioavailability of iron from the supplement. Folic acid, or vitamin B9, is essential for DNA synthesis and repair, making it critical during pregnancy and for individuals with increased cell turnover.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option suggests a lower dose of iron and folic acid, which might be suitable for prophylaxis in some cases but not typically for supplementation in adults with deficiency.
- **Option C:** This option presents a higher dose of iron but a similar amount of folic acid. While higher doses of iron might be used in certain cases of iron deficiency anemia, 100 mg of elemental iron is a standard dose for supplementation.
- **Option D:** This option suggests a much lower dose of both iron and folic acid, which would likely be insufficient for treating deficiency states.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the **National Family Health Survey (NFHS) and WHO** recommend that pregnant women should receive 100 mg of elemental iron and 500 mcg of folic acid daily for 180 days. This recommendation underlines the importance of such supplementation in preventing maternal and child health issues related to anemia.

## **Correct Answer:** B. 100 mg of elemental iron and 500 mcg of folic acid.