**Core Concept**
The Reproductive and Child Health (RCH) program is a government initiative aimed at improving maternal and child health in India. Prophylactic iron and folic acid supplements are crucial during pregnancy to prevent anemia and neural tube defects.

**Why the Correct Answer is Right**
Iron supplements help prevent iron deficiency anemia, which is common during pregnancy. Folic acid is essential for fetal development, particularly for preventing neural tube defects like spina bifida and anencephaly. The RCH program recommends a combination of iron and folic acid supplements for pregnant women to ensure adequate nutrition.

**Why Each Wrong Option is Incorrect**
* **Option A:** Not specified in the RCH program guidelines.
* **Option B:** Incorrect dosage, as 100 mg of iron and 500 mcg of folic acid are standard recommendations, not 50 mg and 250 mcg.
* **Option C:** Incorrect dosage, as 200 mg of iron and 1000 mcg of folic acid are standard recommendations, not 150 mg and 750 mcg.
* **Option D:** Incorrect combination, as the RCH program recommends iron and folic acid supplements together, not iron and calcium.

**Clinical Pearl / High-Yield Fact**
The RCH program recommends 100 mg of iron and 500 mcg of folic acid supplements daily for pregnant women to prevent anemia and neural tube defects.

**Correct Answer:** A. 100 mg of iron and 500 mcg of folic acid.