**Core Concept**
The question tests the knowledge of drugs contraindicated in pregnancy, highlighting the importance of safe medication use during fetal development. **Teratogenic effects** of certain medications can lead to congenital anomalies, making it crucial for healthcare providers to avoid these substances.

**Why the Correct Answer is Right**
The correct answer is a well-known teratogen that can cause severe congenital malformations, including heart defects, cleft palate, and limb abnormalities. **Warfarin**, a vitamin K antagonist, crosses the placenta and inhibits vitamin K-dependent clotting factors in the fetus, leading to bleeding complications. This is a classic example of a medication with a strong contraindication in pregnancy.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while it may have some side effects, it is not as strongly contraindicated in pregnancy as the correct answer. **Option B:** This option is incorrect because although it has some teratogenic effects, it is not as commonly associated with severe congenital malformations as the correct answer.

**Clinical Pearl / High-Yield Fact**
The **Fetal Alcohol Syndrome** is a well-known consequence of maternal alcohol consumption during pregnancy. This condition is characterized by growth restriction, facial abnormalities, and central nervous system dysfunction. Healthcare providers should counsel pregnant women about the dangers of alcohol consumption.

**Correct Answer:** C. Warfarin