**Core Concept**
Category X medications are a classification of drugs that are contraindicated in pregnancy due to the potential for causing fetal harm or death. These drugs are often teratogenic and can cause serious birth defects.

**Why the Correct Answer is Right**
Category X drugs are contraindicated in pregnancy because they have been shown to cause significant harm to the fetus. This classification is based on the FDA's Pregnancy and Lactation Labeling Rule, which categorizes medications based on their potential risk to the fetus. Category X medications are often the result of animal studies showing a high risk of fetal harm or human studies demonstrating a high risk of fetal harm, such as teratogenic effects.

**Why Each Wrong Option is Incorrect**
**Option A:** is incorrect because it is a correct example of a Category X drug, which is contraindicated in pregnancy.
**Option B:** is incorrect because it is a correct example of a Category X drug, which is contraindicated in pregnancy.
**Option C:** is incorrect because it is a correct example of a Category X drug, which is contraindicated in pregnancy.

**Clinical Pearl / High-Yield Fact**
When prescribing medications to pregnant women, it is essential to carefully review the medication's labeling and categorization to minimize the risk of fetal harm.

**Correct Answer:** D