**Core Concept**
During lactation, the body's demand for folic acid increases to meet the needs of the infant, as folic acid plays a crucial role in the synthesis of DNA and cell division. This increase in demand is due to the rapid growth and development of the infant.

**Why the Correct Answer is Right**
The recommended daily intake of folic acid for lactating women is 500-600 micrograms (mcg), which is higher than the recommended intake for non-pregnant women (400 mcg). This increase is necessary to ensure that the infant receives adequate amounts of folic acid, as the maternal plasma folate concentration is a significant source of folate for the infant. Folic acid is essential for the infant's growth and development, particularly during the first few months of life.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because the recommended intake of folic acid during lactation is higher than 200 mcg.
**Option B:** This is incorrect because the recommended intake of folic acid during lactation is higher than 300 mcg.
**Option D:** This is incorrect because the recommended intake of folic acid during lactation is not higher than 600 mcg.

**Clinical Pearl / High-Yield Fact**
Lactating women should consume folic acid-rich foods, such as leafy green vegetables, legumes, and whole grains, in addition to taking a supplement if necessary, to meet their increased folic acid requirements.

**Correct Answer: C. 500-600 mcg.**