**Core Concept**
Glucocorticoids are a class of steroid hormones that play a crucial role in the regulation of inflammation and fetal lung maturation. In the context of preterm labor, the administration of glucocorticoids is aimed at accelerating fetal lung maturation and reducing the risk of respiratory distress syndrome (RDS).

**Why the Correct Answer is Right**
Glucocorticoids, such as betamethasone or dexamethasone, stimulate the production of surfactant in the fetal lungs, thereby reducing the incidence of RDS. This is achieved through the activation of glucocorticoid receptors in the lung tissue, which upregulate the expression of surfactant protein genes. Additionally, glucocorticoids have anti-inflammatory properties, which help to reduce the risk of neonatal complications associated with preterm birth.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the administration of glucocorticoids in preterm labor.
**Option B:** Glucocorticoids do not have a significant effect on fetal heart rate or cardiac function in the context of preterm labor.
**Option C:** While glucocorticoids do have some effects on fetal growth, this is not the primary reason for their administration in preterm labor.

**Clinical Pearl / High-Yield Fact**
The administration of glucocorticoids to pregnant women at risk of preterm delivery is a well-established practice that has been shown to reduce the incidence of RDS and other neonatal complications. It is essential to note that glucocorticoids should be administered at the correct dose and timing to maximize their benefits.

**Correct Answer: B. Glucocorticoids administered to a pregnant lady with preterm labor will reduce the risk of respiratory distress syndrome (RDS) by stimulating the production of surfactant in the fetal lungs.**